It is funny what people can divorce from fiction and what they cannot. Because everything about this series is peak degeneracy. So honestly not that out of place and I for one like it, but I can understand why date rape drug is more comfortable than a nurse fingering a student who is pretty much enjoying it and its the execution.
For one it has the cardinal sin of having the character be mentally deficient in sexual matter. A student acting slutty versus a student acting vulnerable and unaware are two different things. One is consensual the other feel like they are being taken advantage of. Tsubasa not being aware of masturbating and how to do it make her feel younger and make the scenario feel more realistic, which bring me to the next point.
Second, it does feel a bit realistic and realism is the vain of degeneracy, at least for me. Like I for one can enjoy loli's but it can be uncomfortable when they actually act like kids. For some that can be a bonus, as I assume some people probably enjoy the nurse scene more than others, but as a comedic series goes it could have made the scenario sillier.
Third, wait why is there a random nurse joining the yuri scene with one of Toudou harem XD. Like it feel so random and maybe if the Nurse was more interesting like Tsubasa always having a crush on her and exploring it now that Toudou awaken her sexuality, but nope she just randomly appears.
Still enjoy the chapter, I mean its Mochi after all, degeneracy is expected, especially from a series already full of it just done more comedically.