SizeGenetics questions?

I just got my SG, but does this come in ring sizes (base), and I did not know about? It’s pretty tight already at the base and when I want to go in and put tighten the glans I get hard, the SG is like an cockring and I get a big hardon, don’t think this is the right way.

I’m having difficulty’s putting that thing on because of this.
I was already thinking to masturbate before so I can fit in better, but this is also not the way to do it I guess.

Any help? Thanks