Referring to a broad sense of the term awesome or amazing. Roseberries is used primarily as a noun, mainly in reference to Sex, Drugs, and Rock 'n' Roll. Usually used in exclamation and interchangeable with the term tits, ass, rad, sick, dope, chronic, etc.
Look at those roseberries!
Damn she's got the nicest roseberries I've seen in a minute!
These are the best roseberries I've ever seen.. so many trichomes!
Tommy always has the best roseberries guaranteed!
EX. Rock 'n' Roll
This song is the fucking roseberries!
It's got that roseberries vibe to it!