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
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