Which model next?

I currently own the Helix Trident and the Progasm. I find myself going to the Progasm much more frequently. I know i’m not using it correctly, but the way i get the most stimulation from the device is by sliding it in and out of me. For some reason this really hits my spot when i’m standing and bracing myself against the wall. I’ve been trying to practice using the correct way, and while it does offer nice effects, i always end up sliding it back and forth. I’ve been able to have orgasms this way without even touching my penis. I really like the fullness of the Progasm. Can anyone offer suggestions as to which model might work better for me if i want to keep practicing?