A bubble blowfish happens when you are having anal sex and the person on the receving end farts into your dick. The resulting air pressure travels up your urethra. When your about to ejaculate you pull out, the combined seminal fluid and conpressed air cause the ejaculate to bubble. While the air filled ejaculate is still in the air you and your partner try to pop each bubble before they reach the growned.
Dude. I totally bubble blowfished with your sister last night.