They usually shouldn't be that hard to seat down in there. At the very most, a flat bladed screw driver and push down on the bullets until they seat. If there is a tool, I don't know about it...
I have the EC5 tool progressive makes. It's great. On the EC3's, I use a small flat blade with a small brass hammer. I have a 2x4 I rest the connector on, just give it a even blow, and it seats just fine.
The Hot water trick, or just heat up the connector with a butane torch and it will also slip in.
Once you get the hang of it, you won't even think about it.