Maria Sharapova's Butt Gets Pampered by Boyfriend's Face

Maria Sharapova's professional season might be winding down, but her boyfriend is kicking off ass-eatin' season ... in a big way!

The Russian tennis star was lounging in a bikini Sunday in Positano, alongside her millionaire bf, Alexander Gilkes, who decided to order lunch OFF-menu. For some reason, Alex got a face full of Maria's butt.

He was also pretty handsy with the booty -- so, there's little question to what he sees in Maria. Check out the pics, though ... she was stuck on her phone the whole time he was going to work back there.