It's a school life manga and the only part I remember is that they're on a field trip. This one group of girls is creating chaos wherever they go (in a pretty funny way) and the teacher in charge has had enough of their shenanigans and basically grounds them during the trip--there are attempts at supervision and one of their male classmates is roped in to report to the teacher whenever they do something stupid. I think one of the girls falls sick during the trip.

At some point at night, the sick girl wakes up and thinks she sees a ghost in the tv and basically the whole room ends up in chaos bc they're terrified and it turns out to be a reflection of the teacher who had come by to check on the sick girl. More grounding ensues and the teacher has them all stay in their room and tells them not to create any more trouble. Don't think it works.

On the last day of the trip, the girls realise they haven't bought any souvenirs but they've pretty much been banned from everywhere at this point so they just stare longingly at the hotel gift shop. The teacher lets them pick something up to take home and the male student from earlier implies that the teacher is being soft. The girls and the teacher have a pretty good relationship too, I think there was a bit where they tease her for being single.

If this rings any bells, that'd be awesome. Thank you!