Do guys usually get erections from their first kiss?

My school's homecoming dance was Friday night, and I went with my boyfriend. I had a feeling he was going to kiss me, and he did! It turns out that I was actually his first kiss, which is a great feeling for me and all, but I am curious about one thing: I'm pretty sure he got an erection. Is that common?

(Allow me to iterate that I was not dancing suggestively so this wouldn't be the cause, but rather the kiss would be)