look up any word, like turnt:
 
1.
the underside of the breast. usually in large chested women
ouch you hit my under tit...
thats a cup i hit your under tit
by jmal237 January 27, 2008
 
2.
the underside of the breast. usually in large chested women
ouch you hit my under tit...
thats a cup i hit your under tit
by jmal237 January 27, 2008
 
3.
Much like Underboob...

Bottom tit cleavage... (.)(.)

Also... under tatas... and the thousands of others....
Look at that hottie showing her undertits...
by D0c October 17, 2009
 
4.
When a woman (or man) has gained sufficient weight such that underneath their breasts (or manboobs) are two folds of fat forming a smaller secondary cleavage, it can be said that they have developed "undertits". Double undertits may be sighted in rarer cases, with triple undertits being an extreme rarity, while quadruple undertits is the oft-rumored holy grail.
Prima: Holy manboobs, batman! That guy has a set of quadruple undertits!

Secunda: I didn't know it was walrus season already.
by Richard Butts April 04, 2010