Check out Craigslist.

You think that perusing the red-light district would be too risky with undercover cops and aggressive pimps. You decide to check out your local Craigslist site's "casual encounters - w4m" section, narrowing down the search with posts with images only and women between 18 and 26.

Regrettably the results are rather limited:

Young Latina looking to get dirty(: - w4m - 21
Hey guys I'm a sexy 21-year-old looking for a sexy spontaneous guy to have fun and sexy times with, drinks, laugh, and play ;) Then pleasure each other. I'm 5'2", 90lbs, and sexy. I'm super laid back and easy going. Let's have sexy fun tonight!

Young n' Busty REDHEAD - w4m - 23
I'm looking for help paying the rent! ;) I'm 5'7", 120 lb, DD
CONTACT ME! Serious inquiries only please!

School girl roleplay - w4m - 19
By an actual college student. If you want to help me study, I'm 5'5', 115 lb, D-cup blonde tonight then get in touch with me.

Sweet Asian girl looking forward to see you - w4m - 24
Hello guys! If you want some pleasure, I'm an Asian sweet girl is here. I am sweet, sex passionate, friendly, very clean. Let's feel each other and have great time.