Teenagers, men and alcohol?

[Gabrielle]

Me and my friend both want alcohol (we've had it before) but were too young to buy it so she has this thing going with this married guy so I said to her to ask him to jump in for us but she said she's to shy but I could ask him. I don't know him so my friend said add him on fb and start talking to him then ask him for the booze. But she also said he might ask for a favor in return (sexual favour, wouldn't be a problem bt I don't know him)
So my questions are;
Should I do this or just wait outside for someone to get me a jump in?
What should I say to the guy?
How far do you think he'll ask me to go just for alcohol?
Don't give me a lecture or anything on alcohol or prostitution please Thankyou
Sorry didn't know what to put this under