Start in the dead-hang pull-up position. Instead of pulling straight up, pull to your left side, touching the top of your left pectoral to the bar. Descend under control, then do the same thing to the right.
You can also go side-to-side for two reps before descending: pull to the left, hold at the top, transition to the right, then lower yourself. Start the next rep by pulling to your right.
Thibs thinks you're looking kind of small lately. Says your girlfriend's been bad-mouthing your physique, too. Fortunately, he's taken pity on you and come up with some new movements for you to try.