The mama of three has been showing off her body
a lot lately -- including a fully naked photo
last week that exposed her backside -- at the same time as she finds herself at the center of the rumor mill. Last week, after reportedly trying to "work things out" with her estranged partner, Scott Disick, the reality star was rumored to be seeing 21-year-old pop star Justin Bieber. However, a source told ET the two are "just good friends
," adding that Kourtney "wouldn't go there."