You are proceeding in precisely
the wrong direction, and the more you modify the device, the less
useful it will become!
Jim has mentioned lubrication. That may well be of some benefit, but you must
understand how to correctly use the device. Admittedly, we do not believe it is the most appropriate and effective means to achieve stretching but the principle is the same whatever device you use and if you comprehend the principle, it will work to some extent.
is that your foreskin is a wrinkled piece of skin. You cannot
introduce any device through the passage whilst it is wrinkled, you must stretch
it out (lengthways) to remove the wrinkles first.
Here's the universaldiagram
to demonstrate stretching the foreskin out, at which point you can carefully introduce your device and slip it down the "channel".