The Pinch (P) is where you pluck with all three picking fingers at the same time.
It's used instead of a strum when finger-picking the 5-string Banjo.
You can, of course, choose to Pinch any three strings.
Here's another song that is mostly basic forward roll:TMTIMTIM (Thumb Middle Thumb Index Middle Thumb Index Middle)
This song uses many of the same measures as Bile and Mama.
There are only so many notes you can use in a song.
Try using maeasures and ideas from the various songs to mix things up.