It's a combination between sea horse and buffalo. It is a code name describing a really sexy man who is also a father - thus making him more attractive.
Admirer1: Look at that ridiculously attractive guy pushing his son on the swing!

Admirer2: What a sea buffalo....!

sexyhottiehunkattractive
by I.Wish.I.Could.Quit.You December 30, 2011
Get the Sea Buffalo mug.