Term just started and I think every class does have some students who sit in the back (which is totally fine) but sometimes are challenging to deal with when they show some disrespect towards other students who wish to participate.
For example, if their colleague asks a question they start laughing. I try to be nice by asking if their colleague's question reminded them of an incident (in order to get them engaged). They say no and when I turn my back they keep on laughing.
I know I shouldn't take this seriously but I find it challenging at times to figure out how to deal with such kind of students. I know they might not be interested in my material but still want to be physically available which is fine. I don't know how to say enough is enough in a kind way such that they appreciate other students' questions.
This concerns last year undergraduate students. If you have any advice for such situations please share best practices.