think positive dude! maybe she loves the idea and was wondering what took you so long to ask. if it's a no, then it's a no and you can explain to her that you hope nothing changes (tho it likely will). i'd also try the approach, maybe yall could just fuck as friends and try nothing beyond that. you'd be surprised how many women are cool with things if you just approach it honestly - no hidden agenda.
they can land a rover on mars, yet they still have to stick a human finger up my ass to do a prostate exam?! - ricky gervais
