Nipple stag Share definition Flag When a nipple is hard and poking through your clothing. Usually caused by coldness or just being horny. You can still see my nipple stag under a singlet, long sleeve, and a shirt! Nipple stag by Waffbears June 29, 2010 0 0 Get merch Get the Nipple stag mug. Buy Now — $32.95 See more merch