Hello, people of the forum! You might have noticed that a bunch of seemingly valid BURs have just been rejected.
That is because the e621 staff got together and decided that creating the same chain of implications that we have for "penetration" for every applicable verb would be unfeasible.
Instead of having tags that combine genders/forms and actions for every possible action, we are going to implement a system that indicates who is doing something and who is having something done to them, without specifying what that "something" is.
Still in development, more details soon.
Thank you for understanding (。•̀ᴗ-)✧
P.S.: We're not getting rid of the existing penetration implications, they're grandfathered in