Can be part of kink or not. Circumstances, spanker and timing up to you.

+it turns them on
+ almost unbearable
++humiliation / helplessness
++ long afterglow
++ aftercare from one of the nein (but not from a male character for beau or jester)
++ external genital stings
++ attempted but useless stinging nettle cures

- - non-sexy areas being hit (hands, face, back, feet, stomach etc).
- - internal stings!