Ball loops

Recently we purchased the Dr Joel Kaplan 2 Extra Inches Penis Extender with Ball Loop. We got it to expand the positions we can use where I would love deeper penetrative. Fits great not used it yet but planning to tonight. Anyway tried it on when it arrived and wow can't wait to feel the new bigger hubby but the ball loop won't stay over his balls, they slip out as he moves around. He has had the same thing before when using a cock ring so now with the ring he just uses it around the base of his penis and leaves the balls free. With the extender though it looks as though he will be needing the loop to hold it in place during sex.
Has anybody had this problem before?
Has anybody got any ideas to solve it?
He hasn't got the largest balls in the world but they are big enough for my liking.
Thank you in advance.
Ps. We spent ages looking at extenders and picked this one due to being silicone and not too expensive for a toy that won't be used every time be a shame to send it back if it won't stay on.

This is quite common. I think the makers struggle because sometimes if they make them too tight you can't fit them over without considerable pain and too loose then they slip off. Even ones that are really stretchy tend to slip off. I find it's a little hit and miss. With the ones I have sometimes they stay on sometimes they don't even more so when full of lube.

Its like his balls are too small there isn't a waist for the loop to go around if you know what I mean.

I know what you mean. Mine go tight when erect some times and a loop certainly won't hold around them. Nowt you can do about that. Maybe try putting it on when less excited.

So, when you wear a cock ring around the cock and balls it doesn't actually sit on the balls it goes farther back, against the "taint". Can you get the loop like that?