To have an otso is to have an "on the spot orgasm".

A genius boy/man who always has the right answer to everything. He's funny, kind, caring, good loking and sometimes he's also a little bit childish. He might seem annoying to some people but the ones who really know him knows that he is the worlds kindest and caring person. He might be a little bossy and stubborn sometimes but will do anything to make others happy.

Otso is a good looking idiot. He is also a big crack head. Not very loyal kind.

a filipino song and dance made up by Bayani Agbayani

A song and in tagalog made by the filipino artist Bayani Agbayani.
It kinda looks like you're popping your booty while crouching over with your hands on your knees.

In the Philippines, the term describes to a lose streak.