I remember it was like a one shot chapter they made from a different series. It's about friends in high school and they both confessed each other it was a mutual love. They were happy innocently just holding hands, then when they made love for the first time they couldn't stop. They would feel uncomfortable when they weren't touching each other. later they graduated and now they live together. The uke answers the phone and some friends ask to hang out and drink. He arrives and then the seme comes too and one friend sits next to the uke and hugs him or bumps his shoulder don't really remember, they leave early and the seme gets super possesive saying no one should touch him. It turns out the uke purposefully did it to make the seme more possesive of him.

Is it chapter 4 from Kaihatsu muramura mode?

Yes that was it thank you!!!!!