An insider told E! News: "There were fake lines of cocaine on the tables and people bobbing for penis toys in a vat of milk."
A customised cake featured a Barbie doll throwing up in a toilet.
The source claims Cyrus spent the night twerking on stage with her dancers and smoking marijuana.
Big Sean, Vanessa Hudgens, Kylie Jenner, Jared Leto and Rita Ora were among the well-known guests at the party in the club at The Hollywood Roosevelt hotel.
Cyrus' current love interest, Kiwi model Stella Maxwell, was also at the event. However, the singer recently denied they were in an exclusive relationship.
"I'm very open about it - I'm pansexual. But I'm not in a relationship," she told Elle Magazine.
"I'm 22, I'm going on dates, but I change my style every two weeks, let alone who I'm with."
- Bang! Showbiz, nzherald.co.nz