I approve of this manga so much.
Let’s pretend this is reality, as a thought experiment.
Is there any problem with regard to consent?
The action is by the unaware party. Said party will never know what they did. There are no negative consequences to said party’s life.
I truly have no idea at this moment. Probably because my partner or I has been too tired for like a week and my body is doing kegels involuntarily and constantly.