It’s the same Microbikini as in PlayClub.
I know we already had a super risque microbikini in SBPR, but it’s not a thong-type one, and it was easy to port. Besides more is better in these cases.
CharaCustomList_MI.unity3d, ID 209102.
Extract the contents of the 7z to your SBPR main directory. Merge folders if prompted.
For conflicts with cur144’s mods, see his post here for a modified CustomList of his mod.