My Friend's Little Sister Has It In for Me! Volume 7 by mikawaghost

With the culture festival behind them, it’s finally time for some rest and relaxation! Or it would be, were it not for the two-mom tag team ambush being sprung on Akiteru. With both mothers keen on interrogating Akiteru about his relationship with their daughters, there’ll be no time for relaxing at all! While Aki deals with them and tries to figure out what happened between his aunt and uncle, a battle rages on behind the screens as Mashiro and Iroha compete for his affections.

Will things come to a head on the upcoming field trip, or does more disaster await?