Going tanning without a boner (achieved best while facing up for optimal paterns) thus creating tan lines on your ding-a-ling. Then the next time you achieve boner status, it will look remarkably identical to the striping and pattern of a zebras hide.
"Yesterday I forgot to have a boner while in the tanning bed...Now I have a date with Claire to prom and I dont want her to see my zebra dick."
Zebra Dick occurs after anal sex, when, upon removing the penis from the anus, one finds it striped in feces, resembling a zebra with brown stripes. Sometimes referred to as "Tiger Penis" and often occurs in conjunction with Poop Noodle
Last night, I was fucking Cindy, and upon removing my member from her club, I found out the bitch gave me zebra dick."