The official synopsis, as noted by TMDB, states: "Unstoppable gals get out of control! The sex life of an otaku student couple develops rapidly due to the influence of gal schoolgirls". A more detailed synopsis from AniSearch provides the actual plot setup that unfolds across the two episodes:

Storylines often utilize the metaphor of a "social battery." Incha couples understand that after a day of work or school, their energy is depleted. They don't demand emotional labor from one another during recharge time. The relationship dynamic is low-maintenance, highly respectful of boundaries, and deeply cozy.