When one equips themself with "Hulk Hands" and then proceeds to masturbate.

Also see: Super Smashturbating

when a male masturbates harder than he normally does.

It is where you take the time to plan your masturbation session, meaning it involves thought from well before. It indicates the type of porn and porn stars etc are thought of in advance (YOU MUST BE EXCITED FOR THIS). You must be able to watch it with the sound at optimum level and have all videos (downloaded or streamed) ready to watch before you start. You should have the house to yourself so you can pleasure yourself however many times you feel necessary.

the act of masturbating while shitting, not to be confused with smashterbation, its much less strange homonym.

Playing any Super Smash Brothers game by yourself.

Smashturbate:
verb.
The action that takes place post partaking in a few rounds of the popular video game, Super Smash Brothers Ultimate, with a party of 2 or greater, where one is continuing, after all have ceased, lustfully towards gameplay, causing ya homie to play against the computer. and get fucked.

jacking off so hard that your dick bleeds.