I wanted to have fun with my best friend.

A year ago we had a bet and if lose I have to suck his dick. Well I lost the bet but nothing happened since. He sometimes mentions it but as a joke (I think). Today I told him that I would like to suck his dick but he couldnt tell if I was joking or not. Then I told him that I'm bisexual but he didnt believe me. I touched his pants down there and he didnt really moved away but I did not go further and I asked how could I convince him but he didnt tell me nothing. So he didnt believe me. What should I do next time?