It's not that unusual. I've had males do this as well. Cats seem to be a little more casual about gender issues than humans. Tell CB and kitten to stay happy and keep chasing that Rainbow! :)
hi, i have male cats in the house (both neutered & not) and they do this too. i think it's just a loving gesture between, and it hasn't caused any conflict here. they've been doing this for quite some time, so i wouldn't worry.