It's called monster cropping. Best done really early in flower. I just did this, with mixed results that turned into failures, my own doing... I just had mine in cups with no heat pad in a cold room.. 3 out of five got roots after 15 days, 8 days under dome, don't think it was needed, as small buds never thought about wilting.. For some reason, I can't explain, I misted them put a dome on and woke up the next morning with furry mould ball covering them. Sometimes I should smoke less or more and not have energy to do stupid things, lol... It's worth a shot if that's your only option, just don't expect and be surprised if it's a success.. But if it's a success, awesome mother plants and plants that will explode, especially outside. Man I want to get a monster crop outside...
There's also a thread, somewhere on goggle, lol, where the guys done this, littlest buds, once rooted put them straight back to 12/12 and got couple of ounces off of each. He wanted others to experiment with this to see if the results were replicated.