Hello heroes,
So in a playthrough yesterday myself ("Fritz the Sharper" lvl2 Rogue) and a friend ("Jabb Ada Hutt" lvl2 Barbarian) pulled off a move where he slingshotted me at an opponent, and I used the momentum to deliver a swift-yet critical-hitting blow straight to his groin*.
It was fantastically hilarious at the time (and still is... we're grown children), but my friend and I were a little let down that the whole move defaulted to only 1 damage for untrained unarmed combat. I decided to turn to the mighty internet to see if there might be a way that we can go about turning the lucky accident into a written out custom move we can perform at a moments notice. Are there rules governing this and/or maneuvers that invlove 2 people for one full action? Also, please let me know if you have a suggested name for this ancient technique, if it becomes a real thing in our adventure.
Any and all help/discussion is welcome. And if anyone is in the Chicago area, we should chat about a playthrough!
Keep Rolling!
Fritz
*nads/gonads/nutz/berries/ornaments/Dragon Balls/Holy Orbs of Groindaline
this tpe of move are refered in the PHB at the top of page 193 : Improvising an action
Basically what you can read tehre is if you want to do something not describe in the PHB you talk about it with your DM and he'll create the rule himself based with the information he can gather.
Your DM said it was an "improvise" weapon so deal 1 damage. Personally I think this is simply a case of: "I need a quick ruling to avoid overpower and that cannot be contested".
Personnaly I would talk with him out of the game (so no pressure of trying to find a ruling quickly so the game can continue) and try to make up rules with him for this,
Personnaly I would say: The barbarian must do a strenght check to see if he can throw you accuratly and far enought, then you can do your damage with advantage and add the barbarian strenght modifier on top of it.
So For example: you are a rogue with 16 dex using a short sword for 1d6+3 +2d6(sneak attack)
The barbarian got 16 Strenght.
So you ready your action to attack when you'll be thrown.
The barbarian pick you up and throw you DC 7+1 per 5ft, so if you try to reach an ennemy 40 feet in front of you, then the barbarian need a DC 15 it is a difficult task to throw you further then the barbarian can run. If the barbarian fail you take the the barbarian strenght modifier in damage (3damage) and you'll be prone. If the barbarian succeed, then you will deal 1d6+3+2d6+3 over a distance greater then what you and the barbarian could have reach trying to walk toward the target.
The number might have to be balance and verify, but the basic concpet is there
I would simply make the opponent stunned for a turn plus the 1+STR-mod damage for this combination and gave inspiration to the one, who got the idea (or both, if there was no real suggesting beforehand).
Moves like that should get rewarded, as long as you're not trying to make every single attack something like this. Simply because it'll take too much time.
Great job, you two! :D
There are some really good combos in the game.
1). If you have a monk-stunning strike is amazing with wizards. If you land a stun have your wizard cast spells without the possibly of failing a dex save. So in particular disintegrae.
2) Fighter- Battlemaster can grant advantage to allies. some classes like rogues can sneak attack when they have advantage.
3) casting greater invisbility on rogue, this is seriously almost borderline OP.
4). Using knockback combos to knock someone off cliffs, or using spells like passwall to make a whole in the wall for another PC to knock them through.
Tons of combos. This is just the tip.
For something as fun and entertaining as this manouevre, even if the mechanical aspect is less than awesome, the DM can award inspiration as a reward. My DM has done so for things like rolling across a doorway and standing to fire - not because it did much to affect the combat, but because it was fun.
If you were at my table, I'd penalize your to-hit roll, due to the smallness of your desired target. 
But if you rolled a nat20, I'd go out of my way to make the event Awesome.