Helping a friend? Should I? Or is it wrong?

Okay, well, about a year ago, I dated this guy, lets call him Liam, so Liam and I date for like 7 months. Liam dumps me, and I still love him. He goes off and dates this other girl and he has his first kiss with her. In the meantime I date this other guy who turns out to be gay.
So last week I was hanging out with Liam and I kissed him. I had never kissed him before, but I can’t get over how amazing it was. He hasn’t said anything about the kiss. He told me that he is sexually confused right now, and wants me to make out with him to figure out if it’s just a thought, a phase, or the truth. So, should I?
Thought I should mention, I am a girl, and I have never given so much as a peck on the lips.