Kritte Vitte Vitt Bom Bom
The boys can now pick up pretty much any piece in their Guitar Duets for Beginners Volume 1 book (by Thorlaksson) and play it without any practice, so that's a fun progress marker, because we all remember the effort we used to put into getting the timing right. Seeing how you've improved after some months of practice is a real joy. Enjoy this piece.