There are a lot of other dream prolonging techniques, like spinning, shouting for clarity/more time/…
There are a few guides about this like: https://community.ld4all.com/t/dream-control-training-course/31812 (look at the 4th post).
I don’t know how your problem with waking up is related to low-lucid dreams, maybe you were only close to waking up anyway. You could try to imagine rubbing your hands, it will work the same in the dream but you don’t risk to move your real hands.