Having trouble finding my sweet spot?-gctid9821

The first time used the aneros helix Classic it was a awesome session ever had, but the second, third, and fourth time was not so great. My first attempt was lying on my side it did wonders but after that was no go and from that experience I decided to restart from the beginning. I decided to try a new position which is the kneeling position and it did wonders for me, but now than I get too aroused feel like touching my penis.

The problem I am having is finding my sweet spot?

And I am also debating about buying either a the Progasm or the Supple Nipped for my nipples or

Should I stick with what I have which is the aneros helix Classic or do you think I am too impatient for beginner?

Could Progasm feel more of my prostate up?