I have the Helix Syn Trident and the Eupho Trident.
In my nervousness I figured they should go "this way". Something was definitely not right but I got some experience putting in and removing 2 toys and I did dwell with them in for an hour, and it was pleasant.
I was really nervous, heart beating fast, and now that I can easily do this, much more relaxing.
Anyway, I kinda figured it was backwards, but it still felt good.