Does whistle work? P4 could be pipe. I don't know what the other clues would be, but maybe you can think of something. Otherwise I'm ready to be done with this.
The way this plays out is once we decide on either V or M is that Nich & D1 correctly come up with the clue not chosen as well as the R4 and then they guess the answer.
We just need to pick either M5 or V6. I'm leaning ever so slightly toward M5.