18+ Sex & Dungeon!! Wagaya no Chika ni, H Kaisuu＝Level no Dungeon ga Shutsugen shita!?

Souhei embarks on a trip in the gigantic labyrinth that suddenly appears in his basement. But it's an extremely special dungeon where the only way to become stronger is to do lewd things with girls and increase LV (Love)! He collects things from the labyrinth to play pranks on girls. However, the further he goes in the dungeon, the more his relationships with the girls change. The story of a young boy who explores and does lewd things with women.

(Source: Kill Time Communication, translated)