Re-Tale 4 R-18 / アプレットコイル

It's a manga about stargazing, camping, going to the beach and having sessions with sans on the ground.
It's sans / Human♂ and it's lovey-dovey.

It is a Re-Tale series, but compared to the ones that have come out so far, it is more coupling-oriented, so I recommend it to people who like those two.

It's released at the same time as the all-age version.
The difference between this one and the all-ages version is that the sex scenes are increased and the dialogues and structure are slightly different, but the scenario is mostly the same.
As a bonus, a mini-card of the cover of the all-ages version is included.