Newaza practice can be grueling and difficult at times, leading to frustration and reliance on bad technique and pain-compliance type moves. As we are here to learn good form in a safe environment, please take a moment to watch this video by BJJ expert Keenan Cornelius.
Note: regarding pressure point/pain compliance moves and finger grabbing during training. It is one thing to want to emulate live/competition environmemts where opponents may try these types of moves, but causing your training partners to unnecessary pain just showcases your lack of technique and reliance on moves that you can't rely on. It is the gentle way, not the 'dirty tricks that don't work on people who are better than you' way.
Clearly judo newaza and bjj practice are different, so watch with a grain of salt, but the overall lesson is the same: the golden rule applies in the dojo, so do your best to be kind to your training partners!