I’ve always been drawn to punishments involving hands.
Hands are erotic- whether the giver or receiver of the punishment- but not nearly as overtly sexual as naked nether regions or implements. Unlike both other things, they can be left in the open without drawing attention. Except, of course, from those who know what they have been up to in private.
And as receivers of punishment, it places the focus more squarely on the punishment aspect. There is embarrassment to be sure, but not of the same flavor as having to lower one’s underthings and get into an awkwardly intimate position. Though I suppose that is not always need to be the case. With enough flexibility and creativity anything is possible.