Kusum

My guess as a learner

Kusmak = to vomit

kusum = I vomit

kuþ = bird

kuþum = my bird

hope this helps!

Thanks, that´s what I came up with too!!  Friend seems to think it´s a term of endearment.

Might he have meant: kuzum?

I thought Tarkan uses that word in a song. "My lamb".