I have very specific theme in mind, usually with two girls talking, the topic sliding slowly to masturbation, which slowly escalates into showing masturbation techniques, masturbating together and then each other. A pity this theme is not very popular in yuri, even though high school themed manga count for majority of all works
The phone sex scene from Maka-Maka springs to mind. I can't think of anything else off the top of my head that also features phone sex, though I guess ch3 of Is My Hobby Weird? comes close.
>>2367320
Gonna need more examples OP.