The wall with a hole, place it and you can either start sex near it or wait for them to try to fit through it and start sex to them while they are stuck. If they are stuck, you get the same options as if you interacted while they were showering, on the toilet, or sleeping, which is to start sex or do nothing.
That's basically the only way to play right now. If the translation had been done by hand, no, I am not trying to knock the one we got, we would be able to play with the text itself instead of using key words from the audio. It has improved, but it still has a long way to go before it is usable by itself. That's just the way hand translations are, they take a long time to make even with a fully bilingual translator. Hell, the previous game, Koikatsu, isn't much better off. If it weren't for Illusion doing the Party version, we'd still be fully machine translated in that one, too. That said, the situation there is slightly better last I checked because there are people trying to hand translate that one, granted said hand translation has been slow.