Futari Haori wa Saikou no (Sex ga Dekiru) Ibunka Kouryuu desu

It's not a real "helping hands" gag unless you put a little something extra inside (lie). I stealthily gorged myself on the unsuspecting transfer student's wet pussy in front of the entire class… And now I'm hooked.
(Source: Coolmic)
Note: Simultaneously released in long-strip and traditional formats, with 21 episodes and 7 chapters respectively.