The real question should be: How do u know if a guy is serious or just wants to fuck????
Cause im sure if u like dude ..... a couple of cues will let him now you want some action.....
But if your serious about this guy.... dont come on too strong.....
In the past .... sometimes a girl would give me rhythm... and even though i didnt really like her that much...(she may of had a nice rump or rack...lol)
Id still hit it for the experience....especially if we hit it off ...... and then sooner or later it would just end....
It goes both ways too.... I went out with this one chick from my old job.....
She was perfect in ever way to me.....Yeah i started getting really serious.... cause the sex was so great, she had such a nice big booty, and very smart she was....
Eventually she dumped me after a month of fun.....
She eventually ended up telling me she just wanted to bang me and made a bet with some other girl....
That she could have me....
Im stilll butthurt....but it was hella worth it!!!!!
thanks!
how ya doing? 
hahaha