After installing a P-valve to your dry suit, there is always some “knob” and hose that catches on stuff like your dry suit underwear while donning.
Especially the older styles balanced style P-valve with the balancing check valve outside of the actual valve.
What I always do to create a smooth surface again on the inside of my dry suits is to add a protective cover of neoprene over the P-valve.
That way there is no problem anymore with entering the suit.
Not that it is a “problem” without the cover… It’s just more comfortable and smooth.
You start with cutting a piece of thin (2mm) neoprene the size of the cover.
I always lay it on the inside of the suit on top of the valve and mark the neoprene so it covers the entire valve assembly.
Leave some extra room on the top and bottom to secure it to the suit. (5cm)
Glue the top of the cover to the suit so it covers the whole P-valve assembly like you initially cut the sheet of neoprene.
Next you cut a hole on the top to feed the hose through.
Make sure there is no stress on the hose at the hole.
Now you can mark where the bottom of the cover meets the suit.
Here you can glue a piece of Velcro as well at the lower end of the cover.
This way you can still easily access the P-valve assembly to perform maintenance.
And now your basically done.
The only downside I found with this cover is that in case of a dry suit flood, the cover dries slower than the rest of my (trilaminate) suit.