When I am the singer and the guitar player, I shut the hell up and play guitar.
Also you should know that I am under the advice of my attorney to not sing. She went on to add that if I had any problem remembering her advice that she would be happy to make me an appointment with a tattoo artist to help me to not forget.
That's been my MO for a long time now, too - shut up and play guitar. But I'm relieved when someone steps up and sings. Truth is, my favorite thing is to play rhythm behind singers.
I think there could be lots more song writing teams, 'cept song writer egos often dwarf even those of guitar players. Everyone's a Bob Dylan in their own head. A lot of players find/create good grooves, progressions, but lyrics elude them. They should team with a writer, a poet. Easier said than done though, right? Maybe not.