Mariah Carey‘s clearly not onstage a ton anymore … ’cause her choreography was a bit awkward onstage at the MTV Video Music Awards — including a fake slap she really didn’t sell.

The singer-songwriter took the stage at UBS Arena in New York Sunday night to perform some of her hits and accept the Michael Jackson Video Vanguard Award — a lifetime achievement presented at the ceremony each year.

After finishing up a song, a woman in an all-red outfit — who Mariah called Bianca, a reference to a character from the 1999 “The Heartbreaker” music video — came out … and, Mariah pretended to smack her in the face — all rehearsed choreogrphy.

Mariah kept right on performing … and, she got a huge ovation when the show ended — so, it seems no one minded the less than believeable smack.

Worth noting … Mariah didn’t do a ton of dancing during the show — moving around the stage a bit gingerly and holding hands with dancers who seemed to be leading her around. She doesn’t do a lot of live shows, so she might be a bit out or practice.

She sounded great though … and, she thanked everyone when she accepted the lifetime trophy — though she had to ask what took MTV so dang long!