Yeah..I agree with TWP, the whole 'rubbing' thing is just gross...lesbian or not. If this is really making you uncomfortable, you could just talk to her about it. Tell DL that it's okay if she's lesbian, but touching someone else (DJ) like that is harrassment and shouldn't be done in the first place. If the behaviour consists, talk to an adult about it.
If you feel uncomfortable about your relationship because she's a lesbian, just don't say anything for now. If she starts flirting with you or doing the same things to you that she did to DJ, and you just want to stay friends, talk to her about it. Let her know that you just want to be her friend, and that you don't want to go any farther than that. If she feels offended, let her know you're just telling the truth, and that it's better to be truthful than to do something that you regret later.
Oh yeah, one more thing. (You don't have to answer this if you don't feel comfortable)
Why doesn't your family like to talk about lesbians?
I hope I could prove of some assistance.
Love,
CB