In my experience, it's been the married guys that want to touch without asking...the single guys are the ones that stand around and look creepy.
I've not had that experience in a house party setting, but then again, we've only been to houseparties where we at least knew the hosts, if not most of the people there.
And, if some guy was whacking off near me, I'd wonder the same thing...when's that thing going to blow, and will I be in the line of fire. Yep, that'd be enough to take me right outta the mood.
Thanks, Mrs. D....you've officially given me the heebs.
Pepper