Best Organsm

My S/O asked me while we were having sex when did he give me the best orgasm so he could do it again. Idk. I'm not good at the talking during sex thing so I put it off until after. I told him the best one was the first time we had ever had sex. He seemed a little bummed like "I've been trying to knock it out of the park ever since that night. You did most of the work." So I immediately started thinking and came up with a better answer to boost his ego a bit. We had another absolutely perspective night where I had my nails in his back so har he pinned me to the bed. TMI. But literally amazing night. (He ended up bleeding I forgot to file my nails that day). That made him feel a little better but I still don't know how to say the right things or even what to say in bed. I have zero complaints he does an amazing job. But when he asks I don't know how to respond. ANY HELP PLEASEEEEE!