Britney Spears opened up the Billboard Music Awards on Sunday night in Las Vegas with a 7-minute medley of her greatest hits ... including one all about masturbation!

The princess of pop roared through short versions of "Work Bitch," "Womanizer," "I Love Rock n Roll," "Breathe on Me," "Slave 4 U," "Touch of My Hand," and "Toxic."

With lyrics like, "Another day without a lover/The more I come to understand/The touch of my hand," her song choice was a bold one for primetime!

While she didn't sing a lick, instead lip-synching the entire thing, Spears did show off some impressive dance moves ... most notably when she pulled off a backflip mid-song, and followed it up by grinding on some hot backup dancers.

It should be noted almost all of the choreography was taken directly from her "Piece of Me" show at Planet Hollywood, including riding the giant guitar during "I Love Rock 'N' Roll."

Unfortunately, no new music was heard just yet either ... guess we'll just have to wait a little longer for that one!

Get a glimpse at her performance above -- what did you think? Sound off below!

0522_brit_insetLaunch GalleryGetty2016 Billboard Music Awards -- Red Carpet

For more of the night's biggest moments, check out the video below:

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