I think it didn't do well because when BS debuted on BB's Hot 100, TAB was still doing great and BS got repeatedly pushed back because of TAB's success(BS's debut on hot100 singles #74, hot100 airplay: #68 and top40 mainstream:#38; while at the same time TAB was #6 on the hot100, #2 on hot100 airplay, #15 on singles sales, #7 on top 40 mainstream, #15 on Rhythm/C.O. and #2 on adult compempo. It was also charting on hotR&B singles and on R&B singles sales)
The next week, when BS got its peak, both hot100 airplay and top40 airplay didn't make it to the charts, so that meant radio only wanted to play one Madonna song and that was still TAB. That week it only charted just one week on top40 Rhytm/C.O. and then disappeared too. BS's peak was mainly because of sales.
I loved the single and i remember that a friend invited me to go over to a Madonna video premiere on his dorm with his girlfriend and his friends and we saw all her MTV special pajama party and then the music video on a huge screen and it was very cool and sort of an event.
I wasn't a fan of TAB and liked BS and what do you know TAB became her biggest hit and BS, well, not!.