How do you deal with that situation where your friend's toddler pushes or snatches something from your own toddler and they both start screaming/tugging on a toy? Leave her to sort out her child? Grab the bloody toy and give it to the other? Ignore them and let them fight it out?! Clearly they have to learn to share and we all have different approaches to discipline - it can just be so awkward in the moment!
Whoever had it first gets it back until they've had enough of it. The minute they put it down they've lost the right to play with it. Any toy which is causing continuous problems is removed. If all toys are problematic they are all removed and a game like hide and seek is played instead. If they still can't get along then I take my daughter home and try again another time.