Well, there is a technical term for it but I have no idea what it's called.
Generally, the solution is to clean the track or groove that the flap closes in to seal the toilet from the tank. Sometimes it is closed too early and pushes TP or OTHER debris into the groove and not allow the flap to properly close. You at full hookups??? sometimes you can use the spray wand to wash the groove out. If not then a small soft scrub brush will do. Worst case is a wire the same size as the groove - drag it around the groove to clear it out. Prevention is to make sure all the goodies are past before closing.
Michael & Tina with Layla and Preston BZ
The family has grown.
2003 22' INTERNATIONAL CCD