Miley Cyrus -- In Lust With Stella

Miley Cyrus and Victoria's Secret model Stella Maxwell are not pranking anyone ... they cannot keep their hands and lips off each other ... so say the people who hang with them.

Their make out session after a video shoot this week had a whiff of doubt that it was real, as opposed to something promotional for the new song. But people who were at the shoot tell us Miley and Stella were inseparable during the many hours it took to get the shots.

They constantly kissed, caressed, held hands, and Stella got very comfortable on Miley's lap.

People who have been around them recently say the relationship is highly charged, not so much romantic as full-on lust.

Short story ... it seems real.