How can a guy tell a lady 2 who sat down opening her legs n showin her under 2 sit down properly & also how can a lady tell a guy who forgot 2 zip his trouser 2 zip up.

If its in d private, use oral; if public eye/facial communication.

AT A GUY: bro, your fly is undone
AT A GIRL: i would first try to figure out if she is trying to "entice me" or just clueless. either way i am going to have an eyeful before making a move.

If am d one faced wit dis scenario, I'll tell d guy plainly to zip up. I actually did that 2 day. However, if it is a girl, I would tell another female preferably an elderly female to help tell d lady who's entertaining everyone. I wld also recommend same for a girl 2 a guy, though some guys wldn't even mind if a girl tell them straightaway.

I wouldn't do nada! Most (if not all) women would react a bit negatively to that e.g she could regard as a pervert who has nothing better to do than to stare at unwashed undies of the ladies. Women have this funny negative way of "reasoning" so I can't be bothered.

^^