Having intimate relations with someone is putting you in your most vulnerable position. It is an expression of love, or should be, and if you don't love someone or you aren't sure if they love you, abstain. Its easy to get hurt when you have given yourself to someone who just considers you someone to have fun with.
I would agree with Harley about sticking to one preference. Your body belongs to you. Have respect for it. I'm not a prude, but I do believe that sex is not something to do just because it feels good. It should be more than just scratching an itch. Decide which gender you feel most attracted to and then get to know that person well before giving yourself away.
Sam2