Universal Headrest Mechanism?

You can create a temporary headlock using a correctly sized rubber “o” ring as the gland restraint, combined with strong yet thin string—dental floss works well. Since every cage design differs slightly, you might need some ingenuity. The process involves attaching the string to the ring, positioning that ring behind the glans, threading the loose end through the cage structure, and locking the cage down. By tying the free end of the string to the front of the cage (I’m using an A273 model), it stops me from retracting.

It takes a bit of time to locate the right ring size and adjust to not being able to pull back, but results look good. However, it doesn’t add much extra security because cutting the string is straightforward.

I recall that Pedro69's KHD cages available via Shapeways featured a slot on the underside of the glans designed for a thin O ring. This ring would hook over the top edge, then slide up alongside and settle into the locking block. I don't remember the exact diameter; it likely varied depending on how long the tube was. The cross-section measured around 2mm (3/32"). I believe this feature was specific to the X3 and Q4 series models. It could be worth checking out for some inspiration.

My main worry about placing a ring behind the glans is how easy it will be to clean underneath. I've been considering trying this approach for some time now and hope to find an O ring that slips easily into my A272 without catching or pinching delicate skin.