When two males perform double anal penetration on a female's (or male's if that's the way you swing) anal cavity and both precede to move away from each other while still inserted, thus forcing the anal cavity to spread, or rip depending on your level of arousal. This can cause feces and blood to spill out onto the "can-opener's" junk. Precede with caution.

When a one-toothed bitch rips open your ball bag.

a derogatory term for a male homosexual

The can opener is when the male proceeds to do her from behind and puts both thumbs in her butthole.

Such a fierce buttox explosion that the methane all comes out at once. Causing the cheeks to fully seperate, and observers to flee.
Almost toxic.

I alone control the Can Opener...The Can Opener obeys only me.

A vagina with tremendous muscular control; e.g. capable of opening a can.