Hello. Hoping someone can advise me. We have a clean water leak from the back of the toilet every time we flush. The pipe has been installed at a bit of an angle which is compressing the rubber grommet (no idea if that is the right term) and that is why it is leaking. I am hoping I can fix it without having to remove and refit the pipe/toilet. Can I use some of this plumbers sealant stuff or PTFE or buy something else to cork the gap or do I need to take the pipe put and cut it shorter?