There are many things that annoy me about all those "learn to ready body language" lists of cues you see in magazines and self-help books. One is that half of the things they tick off are completely fucking made up. The thing where liars supposedly look to one side while thinking, and truth-tellers to the other? Bollocks. People look away from the speaker for lots of reasons. They're thinking and they don't want to process visual input on top of that, they're trying to escape the conversation they're having, they think you're some sort of frightening madman continually scrutinizing their face for imaginary signs of deception, etc. It means nothing. And, in fact, some of the most accurate truth-tellers you can find will wobble their eyes all over the place -- it's not uncommon for eidetickers to exhibit eye movement corresponding to what their real eye movements would be if they were checking for details on an actual photo held up in front of them.
Over-simplification is another bitch. A lot of these things will tell you that hemming and hawing and other sorts of delays are signs of deception. They're not. What they are signs of is that the person speaking is under cognitive load, which is the technical terminology for "thinking about what they are going to say/do and running it through a filter before it gets out into the open". Liars who are making up their story on the fly do often show signs of being under cognitive load, but so do people who are terrified of making some sort of social misstep all the time, people who aren't sure what the answer is and don't want to look stupid, people who are trying to phrase things very carefully, and people who think they may be about to tell you something absolutely true that you aren't going to like. Cognitive load by definition takes up processing cycles that might otherwise be devoted to controlling your behavior or running your mouth, so if there's too much internal work involved, your outward presentation starts to stutter a bit, like trying to run to many programs at once on a crap computer.
The thing that makes me really want to throw the self-help books at the wall, though, is that none of them acknowledge the overwhelming importance of context. In order to read people accurately, you need a hell of a lot of context along two axes: One is that you need to know what sort of social behavior is going on around this person right now, and the other is that you need to know how this person has generally acted in the past. You can cheat both to a large extent by remembering how other people have acted in similar situations, but that itself requires you to have paid attention to previous experience. Eyes for Lies, who specializes in detecting deception and has done most of her write-ups on criminal cases, has written up some of the specific ways she gets her guesses about the people she spotlights, but mostly it's just a game of spot-the-pattern.
seawallglen asked a question a few days ago that tangentially mentioned the fact that about half of the YouTube comments under a particular ep of NMTB were speculation about whether Fielding hooked up with the woman who happened to be on his panel that day. Sexual attraction and/or romantic interest are difficult to decipher sometimes, mostly because those things are not themselves specifically-defined, visible behaviors -- rarely if ever do people answer the question of 'are they or aren't they?' by having sex right in front of you, for instance. What people key on, when they wonder about this stuff, are a bunch of what linguists call indexicals, or things whose existence indicates the existence of another thing you can't directly see. The canonical example is that smoke is an index for fire. Generally what people key on for romantic interest are behaviors that say "I am getting attached to you," "I am feeling affectionate towards you," and "I want to have your attention."
You will probably see the main problem with this if you think on it for a second, which is that none of those things are specific to sexual attraction. People engage in these behaviors to for a number of reasons and to widely varying degrees, dependent upon culture, venue, and current company. Thus, in order to figure out what they actually mean, you need your axes of context. Smiling, laughing, hugging people, and drinking cocktails is not remarkable at a party, but would make you wonder about the sanity of a soldier who attempted to do that in formation. Likewise, a friend who has always been terrifyingly shy in large crowds suddenly deciding to take off their clothes in a restaurant might be rather alarming, but you wouldn't think twice about a professional stripper working in a topless bar doing the same.
In the specific case seawallglen asked about, the comments are like that because the comments on pretty much all of Fielding's episodes of NMTB are like that, except the ones on the shows that went badly enough that the internets are inspired to complain. Watching more footage of him in the same social context reveals that this is how he always acts towards anyone he finds at all likable, given half a chance; he's been much the same towards Ed Sheehan and an extraordinarily gravid Martha Wainwright, among many others. In order to figure out whether something is weird, you have to know how it goes when it's not weird. That's pretty standard for Noel Fielding, so I don't think it's remarkable -- I hadn't checked the comments on that one, in fact, and it had not crossed my mind that he was paying any special kind of attention to Schaal, although he does quite clearly think she's fun.
I do quite understand why people would think that, though. Fielding is rather strange, to put it mildly. For most people in western cultures, the default is to maintain a polite mental distance and keep your paws off of people; acknowledging that you've connected up with someone over something, especially if you want to do it with a physical gesture like a hug, requires a positive decision. Even socially-comfortable people will typically show a spike in cognitive load before they try it on someone who is a relative stranger, as they double-check that all the various verbal and non-verbal signs are a go.
Fielding seems to work just the opposite. His first and evidently very strong impulse is to touch people; he has to put some effort into stopping himself when required, although he always does, and when someone who has previously wanted him to keep his distance changes their mind and gives him permission, his cognitive load drops like a rock in hard vacuum. I'll save you some time and tell you that he spends the first twenty-five minutes of this interview fussing with his hat, keeping his free hand pinned in under his elbow, developing a keen interest in the toes of his shoes, and leaning away from her every time he makes eye contact -- until she touches him, at which point he's immediately all better.
As to why he's like that, I can only guess. If he wanted to cling out of insecurity, he'd be doing it to people he knew but not to strangers; if it were some sort of social power play or bid for attention, he'd be doing a lot more boundary testing (i.e., he'd be trying things to see if he could get away with them, rather than watching for signals). To the best of my ability to determine, it really is just that he likes people, he likes liking people, and that's how he's most comfortable communicating. His favorite people are near-universally the ones that don't make him think about this at all -- he's not all over his friends because he's made some sort of decision to be physically affectionate, they're his friends because they're the people with whom he does not have to constantly check himself.
Having now seen the Boosh TV pilot, I have this nagging suspicion that someone actually told him and Barratt to quit standing on each other's feet all the time. It's SOP for them, but it can get summat distracting if you're not already accustomed to watching them do it. It may also be why the character of Vince was revised to be less dependent and childlike -- when Barratt as Howard is trying to do the sort of fatherly, hand on the shoulder, explaining his plan to the idiot thing, Fielding is having a really difficult time not just stepping into the gesture and adjusting their body language back to equals.