If you've already done this on several occasions in the past, sure, use your discretion and interpret body language or subtle signs. Otherwise, ask. Period. No exceptions.
That's why you can end up repeating mistakes over and over again and annoy/intimidating people you don't even realize you are annoying/intimidating, even tho that wasn't your intention at all.
> use your discretion and interpret body language or subtle signs
Making it sound so simple disregards the fact that this isn't natural to everybody and it's not really an easy skill to learn when it's not natural to you, especially not on your own.
Sure you can ask about all the things that everybody else considers "normal", but do you really want to stick out even more as the "oddball" than you already feel for being insecure about such seemingly "normal" things?