The Brief: Rolly is slang for a Rolex watch.

DEEP DIVE
Rolly or Rollie (pronounced as such) is slang for a Rolex watch. It is the subject of the song “Rolex” by Ayo and Teo.
I just wanna Rolly Rolly Rolly with a dab of ranch
I already got some designer to hold up my pants – Ayo and Teo
I thought "rollie" was slang for Rolls Royce because… cars roll, but listening to the lyrics of Non Stop by Drake, I now understand that a "rollie" is a Rolex. Sigh. Getting old is hard.
— roxane gay (@rgay) September 4, 2018