The indentation between your tailbone and your cornhole; it is the counterpart to 'taint'.
Some Helpful Information: A lot of smelly stress gets built up in your tot (especially if you're a huge fatty and have trouble reaching it), so make sure to keep your tot clean! (and you should probably also lose some weight if you experience the aforementioned impetus to tot-cleanliness.)
This PSA brought to you by the Clean Your Tot! Alliance Foundation - helping to keep tots clean for a fresher tomorrow.