Hard to do cause they’re often so sneaky about it, but per the other thread on this subject, what do you do? What can you do? What should you do?
Watch quietly, reciprocate later.
I really had it happen before with my very attractive female roomates. I just watched for a couple of minutes before I worried about being caught so I left.
Boy, does this question need qualifiers!
[ul]
[li]Do I know her?[/li][li]Where is this happening?[/li][li]Are there other people around?[/li][li]What are the circumstances?[/li][/ul]
I would not be offended, for the most part, but I need to know more to answer with something other than more questions.
I say, “Mom, damnit to hell, stop doing that in the living room!”
Of course.
AAAAAAAAAhhhhhhhhhhh! My EYES! MY EYES!!! AAaaarrrrrrrrrrrgghhhhhhh! :eek:
Women don’t masturbate… do they?
Hell yes! We absolutly do!!
Of course we do! And my SO encourages me to indulge in front of him whenever the mood strikes. It’s all part of the lovin’.
throw-up
I’d probably stare for a couple seconds, not quite believing what I was seeing, then giggle quietly and walk away.
I figure they wouldn’t want me watching them, so I’d respect that. It would be hard though.
Yeah - I’m sure IT would be hard all right. 
ahem It would be difficult though.
I’d be embarrassed and get out of there quickly, averting my eyes as I went.
Depends on the day, the mood…if we’re assuming it’s a complete stranger … well, I am afflicted with Chandler Syndrome, which means I feel compelled to make quips. To wit : “Need a hand?”
I’d wait for the funky Wah-wah to start, then walk in and “introduce” myself! 
WAKA CHIKA WAKA CHIKA WAKA CHIKA WAKA CHIKA WAKA CHIKA WAKA CHIKA
There you go, gatopescado
How YOU doin’, Masturbatin’ Lady?
I’d plotz.