.

You were uncertain about escalating. In her mind its the difference between "are we doing this?" and "oh shit we're doing this!"

Hmm I don't know, I was pretty certain apart from that one point, that can't really have made a difference. 

I was thinking before that maybe I put too much responsibility on them, I didn't push the idea enough and left it to them to decide

Yes Ruby's correct 

Can you expand a little more then, I don't really understand

Your escalation SUCKED. You needed to do way more, be way more forthright about it, just DO IT. Instead you were shy about it. That's NO way to create the kind of sexual momentum/dynamic you need to make a threesome go down. These girls got to get swept away, you were unconsciously waiting for signs of compliance/attraction/"ok this is ok". 

Ya I think I'm getting what you mean now. Obviously it was adequate enough to get them to come home with me, but once they were in my bed I slowed down way too much. I should have been escalating HARD since they were in my bed. I played it way too safe and was only escalating when I was sure I'd get away with it.

If you asked me theoretically what I'd do to those to girls if they were in my bed I'd imagine something way more agressive than what went down, so clearly that gap was me being a huge pussy

Fuck that dude. I'da told them I wondered if either of them could wrap their hands around my cock because it's pretty damn wide and I don't think so

I can't believe I didn't even get my dick involved, rookie error

Sure. But what else is involved there. You're falling for the "easy" answer not bothering to look any closer. 

Well as soon as one girl left my dick was straight out and I escalated ruthlessly - so I must have a mental barrier when it comes to escalating on two girls. I froze up and got in my head just because I was a little out of my comfort zone