My-Steel: Chafing on the underside of the penis

I have a regular My-Steel male model with a stainless steel penis tube. In the past weeks I have tried to wear it longer and longer, but now I regularly have chafing on the underside of the penis. Perhaps it is easiest to see this with a model image. The wound is where I have marked the red line:



This must be caused by the lower part of the entry to the penis tube. Especially at night when I toss and turn in bed, there is pressure and movement of the penis tube against my skin. As a lubricant I use coconut oil and I have also tried rapeseed oil. Both of them work much better than water based lubricants that I had before. Also I have tried to put a piece of cotton fabric over the edge of the tube, but that did not prevent damage either.

I have tried to make the waistband tighter, but that did not seem to reduce the movement enough to prevent damage. Perhaps the increased pressure has negated the effect. Also I have tried to move the penis tube one setting lower such that there is less pressure on that region and perhaps more on the top side. After a short while there was pain in the area so I figure that I cut off something.

Do you have any ideas how I could make my belt more wearable?