Two gay friends fooling around?

Okay, so today, for the second time, i fooled around with my friend; we're both 15. the first time we did it, i came right away, but this time, i couldn't even stay hard for that long, and he sucked me for a long time, and i did the same for him. we didn't even c u m for each other. i still enjoyed it a lot, but what do you think could've caused this?