"Greasing the groove" or GtG is a training method developed by Pavel Tsatsouline, and made popular through his book 1999 "Power to the People! : Russian Strength Training Secrets for Every American."
How do warming up fits into this system?
If you do several sets of pull-ups (or push-ups or whatever single exercise you'll try to optimize), are you supposed to do a proper warm up every time? Or it's OK to skip warm up, but then be extra slow?
From a purely pragmatic point of view, it seems extremely difficult to fit in warm-ups every time you decide to perform your push-ups.