Lapdist vs Boston

I have just received my new kit from Lapdist. Only 6 days from Long Beach to Italy!
Great service.

I needed some male and female couplers and some hose ( this one is free from Lapdist), and I also bought a 2.25” x 9” cylinder.

I am using a 2” x 9” cylinder for 1 year and a half now, but my glans is wider than 2” while my shaft is still under 6” girth.

I would like to create a sort of cock ring at the base of my new cylinder similar to the Boston ones.

I don’t think my balls will be sucked into the new cylinder, but with some constriction at the base I think the expansion of the shaft will be better.

Any advise how to do a restriction of the base of my 2.25” new Lap?