Term to refer to a mans balls after recently being shaved, when the small prickly hairs begin to grow back and poke his penis as it hangs over them.
Guy: Damn, I got the cactus effect. Should've shaved better.
Guy 2: I know, that shit sucks. Feels like tiny needles stabbing your dick.
Guy 2: I know, that shit sucks. Feels like tiny needles stabbing your dick.
by PurplePagan May 20, 2007
The cactus effect is the feeling when you've newly shaved your balls and your sack stings your penis.
by D-bed December 17, 2011