callipygian

Having beautifully shaped buttocks.

[…]we soon once more were in a state to renew our delicious combat; and a second course was run in the delightful callipygian recesses of Venus’s second temple of lubricity.

Suddenly the music grew fainter, as if drawing away, and the dancers, their feet together and limbs half opened, descended in a slow spiral, with gentle undulations, until they touched the floor; the instant their callipygian charms grazed the mosaic, they recoiled like suddenly awakened serpents, […]

Specifically, describing a statue (often of a goddess such as Aphrodite) in a pose that shows off the figure's shapely buttocks.