The 27-year-old US glamour model, who is the third wife of 87-year-old Playboy founder Hugh Hefner, posted the snap of her Cavalier King Charles Spaniel Charlie enjoying a well-earned nap on her derriere as she soaked up the sun over the weekend.
And it looks as though Charlie's managed to fit his furry small head perfectly between her buttocks (whilst also conveniently protecting them from severe sunburn).
The couple married on New Year's Eve in 2012 in front of friends and family at the Playboy Mansion in Los Angeles.
They had originally planned to tie the knot in June 2011, but split days before the wedding. Their break-up prompted last-minute changes to the cover of July 2011's Playboy, with a hastily-added sticker dubbing Crystal the "runaway bride".
The pair dressed up as Robin Thicke and Miley Cyrus respectively for the Playboy Mansion's annual Halloween party last year.
Hugh shared a picture of the couple twerking together on his Twitter page - sadly sans spaniel Charlie.