Devin Booker Tells Kendall Jenner 'Come Rub It'

Devin Booker is trolling his ex Kendall Jenner over her marital status, sports betting, the Super Bowl, and his bum ankle ... and things got sexual.

The hilarious back and forth is going down in the comments on Michael Rubin's Instagram post.

It all started when the Fanatics honcho shared a clip from Kendall's spot with Jimmy Fallon, where she got Tom Brady on FaceTime and picked a Super Bowl winner to bet on.

Devin commented, "I bet a million the Seahawks get that ring before you do" and he tagged Kendall, who decided she'd bet on the "underdog" New England Patriots to win Super Bowl LX.

Kendall responded, "🙄 how’s the ankle?" and Devin told her, "come rub it."

The Phoenix Suns star used to date Kendall, and they both have never been married. Devin's never won anything close to a Super Bowl, aside from a couple Olympic gold medals with Team USA Basketball ... but, LBR, if Kendall was on the team, they would still win gold.

Devin sprained his ankle in Friday's loss to the Atlanta Hawks ... and he's expected to miss about a week ... so it seems he's got extra time for social media commenting.

Kendall's been pushing the Fanatics Sportsbook hard this week ... filming a commercial for the gambling platform that pokes fun at the so-called "Kardashian Curse."

The advertisement shows Kendall in a classic car ... and right after the ad dropped, Devin posted a photo of himself in an SS Chevy.