Simulate two-finger mouse click and drag

I am trying to simulate a situation where I click with my thumb, and then move the mouse with a second finger and drag (whatever I’ve clicked on) to another position on the screen and then release.

I’ve tried several combinations but have not quite gotten it. I’m working with a very specific web application written in HTML5 (in Firefox). It’s odd, I think it should work, but doesn’t.

Is there something special about the two-finger movements on the trackpad?

This is what I’ve tried:

“Click and Hold”
“Pause 1.5 seconds”
“Move Mouse to…” (just move)
“Pause 4.5 seconds”
“Release Mouse Button”