Picture

Boy butts #6.

Titian
Venus with a Mirror,
c. 1555.

Tiziano Vecelli (c. 1485 – 1576), known as Titian, was a painter of the Italian Renaissance in Venice. He studied under Bellini, and taught Tintoretto and El Greco. He's best known for his use of color, especially rich reds and blues, so this may not be the ideal example.

But it does have a boy's butt in it.

That putto is Cupid, who is often depicted, as here, with his mother Venus.

Cupid, at Wikipedia.

A Cupid by William-Adolphe Bouguereau,
c. 1880.