sitspot

plural sitspots

1. The central part of each buttock on which a person rests while sitting.

   He knew she was close to releasing so he gave her one very hard smack to each sitspot.

   Kate Bullis, Finding Kacie (page 139)

   2 more examples

   Shortly it is to be shorn of its standardization, its monotony of same acts and faces and same whangs on the sitspot. Vaudeville has cleaned house. The old order changeth. It is in new and capable hands.

   1929, Life, page 26

   Another strike across her ass, then another a little below, and then he landed the last at the most sensitive point, her sitspot, the place where her ass curved into her thighs.

   2017, Jennifer Bene, Tying the Knot