classmate
You call the art department at any nearby college or university and ask if they are hiring "life models" for their art classes. (That's the term for people who pose nude for students to draw or paint.) If you mention that you're interested only in posing for female students, they'll probably assume that you're cruising for dates, and they won't hire you. Being prepared to pose for both female and male students is your best bet.

Paws Up
You have no choice. You WILL have to pose for male art students. Many of them will be straight. They're just doing this to study the human figure. Its not like they're checking you out. And if you're doing this to get dates, think again. The art students aren't allowed to talk to you.

Tim D
You don’t, you are just a poseable doll you work for an art college if the students are all male you still pose for them. Having a “nice” body is not required, in fact artists like to draw people of all shapes and hues. If you ask to pose for women only you will not get any work.

SuperDem
Male models are a dime a dozen. There are literally dozens of men willing to model for every 1 position. Most likely, you will need to try and join a guild, or answer craigslist ads. Other posters are correct, body is not what's important, but experience is. Most likely, you will have to gain experience posing for mens groups and hoping to get referrals for future work. Judging from your question, I'm guessing this is not the job for you. Sounds like you need a dating agency.