Is there any way to have sex with the hookers in this game?  I have all this money saved up and I wanna spend it on the hookers, but it won't let me have sex with them.  Also, is there any way to have sex with the other women in this game (some of them are pretty hot)??? 

Just watch porn?

 You want to find one either over the internet, or on the streets. You never want to specifically mention that you're paying for sex, for if she's an undercover cop, she can/will bust you. She'll call a "date" or something of that nature, or a "massage". Ultimately you want to protect yourself from undercover officers. They can put make-up on to make themselves look trashy, or that they have missing teeth. Don't be fooled. Put the money in an envelope and write "donations" on it, leave it on the dresser. Don't hand her the money directly, this is key!
 
Also, make sure you hide your wallet/valuables. It's also not a good idea to take her back to your place. Wear a condom!
 
EDIT: Oh shit! You were talking Assassin's Creed!?

i highly doubt you see any sex ; ; 

I never got why people ever sought digital boning. Especially as tame as video games tend to make it. ME2's was kinda fun in the sense that I actually wanted my character to have that relationship, the sex just... sealed the deal. 

*bangs head on desk* OF ALL THE STUPID...*bangs head on desk again* REALLY?!