ah.. im gonna be philosophical about answering this..
there's nothing that can stand on 2 legs only. you have to have at least 3 legs to stand up. this is like simple physics.
Now imagine humans have 3 legs, except that one of them is "invisible", nonetheless it does exist.
what you have to do is trip the third leg to easily put the person down. so if your friend is pulling you, or resisting, he is pulling towards his backside, that means his third leg extends from his waist to somewhere behind him. all you have to do is trip that leg and push towards it.
in practice what does that mean?
to trip the leg, you either have to be there pulling more than that leg can carry, or you can uproot that leg by having your center of gravity lower than his, and then push towards where that leg is.
in other words you do not want to be higher than he is, and you do not want to be resisting the direction of his energy. you have to go with it, and if necessary just redirected but never against it.
this isnt the only way you can take down a big person. i was surprise d how little the energy is needed to trip a much bigger person.