The Brief: To be "back on your B.S." means to be back to your old ways, specifically your bad habits.

DEEP DIVE
Well if you look at the time
12
11 ^ 1
10 | 2
9 ⊙—-> back on my bullshit
8 4 o’clock
7 5
6— tom (@TommySobiesski) November 16, 2018
Yes I am somewhat back on my bullshit
— rhea butcher (@RheaButcher) November 15, 2018
Back on my bullshit never trusting a soul again🌧
— 🥵 (@petttyy_quotes) November 12, 2018