I remember 1 Trillion and Long Bed releasing a single called "Rar" which was popular in Japan. The user might be referring to a remix or a collaboration of that track with Post Malone. However, I don't see any official releases with Post Malone featuring on "Rar" or "Long Bed". So maybe the user is confused, or there's an unofficial remix that's circulating but not officially released.
(Vinyl or CD) of the Long Bed edition, or would you like to know more about the guest artists featured on the album? Post Malone F 1 Trillion -Long Bed- rar
F-1 Trillion (Long Bed) Digital Album (Explicit) - Post Malone I remember 1 Trillion and Long Bed releasing