i believe it's a spelling improvement program.... 'balloning"?
Don't be too fast to criticize! Balloning (with one O) is a ballet term, referring to the act of appearing to float motionless at the top of a jump:
I believe this could have sexual application-- One of the best lays I've ever had was a member of the San Francisco City Ballet, who did indeed do something like this on my cock.
On the other hand, if Ballooning was intended, there could be many things:
This could be the thing that my friend Alex (with an extremely generous foreskin) would demonstrate in the swimming pool, when he would put his dick into the filter pump outlet hole, and blow his foreskin up like an inflatable ball. I guess any inflation of sexual body part would qualify.
Now, there is such a thing as a balloon fetish, but such people call themselves "looners," so presumable this would be "looning." But apparently this is mostly for people who play with and pop the balloons, but not when they cum in them like this:
And then there is the pinching off of the penis/foerskin while the guy is trying to piss or cum...
And in a non-fetish sense, ballooning occurs with with phimosis, and refers to urine becoming trapped under the foreskin.
Phimosis | UCSF Department of Urology