Houkago Tea Time by Fujieda Miyabi, Minamoto Hisanari, Mizuki Maya, and Nogi Hikaru K-ON! Doujin — Ongoing

Untitled
Chapter 1 released Jul 3 '09
Chapter 2 released Jul 7 '09
Chapter 3 released Dec 18 '09
Chapter 4 released Apr 21 '13