I'm noticing the further we get with these single-appearance nobodies, the less documentation they have in the online fandom. This gentleman appears in two scenes but has no dedicated page on the Simpsons Wiki - either of them.
Here he is tastefully covering Michelangelo's David's penis, even though it was shown seconds prior. Part of me is tempted to do a list of times genitals have appeared in The Simpsons, but maybe that's best left for another time.
David makes two more appearances in the show, with less FILTH on display, in season 9's "Lisa's Sax" and season 34's "One Angry Lisa":

It's somewhat ironic that "Itchy & Scratchy & Marge" is making the point that David should be seen by all, when future appearances go on to censor him. But I'm not here to make an argument about the acceptable visibility of a cartoon ding-dong, especially considering his name.
This post is part of my "Every Simpsons Character Ever" series. For a list of my rules in this project, click here.