Adult PC Game: In'en no Yu ~Sandai no Okami-tachi to no Mikkou~ by Ammolite Archive

Tatsuhito is working in an inn that is owned by his wife's family working together with his sister-in-law Mako, his mother-in-law Mizuho, who is the current landlord of the inn, and his grandmother-in-law Nanao. His wife recently gave birth to their first ch*ld and as a result their sex life decreased considerably.

After an exhausting work day at the inn he comes across an hyponsis program while playing around with his smart phone.
Not believing in such nonsense he shows it to Mako who jokingly proposes that Tatsuhito uses it on herself, Mizuho and Nanao with the condition that they'll always get horny when they see Tatsuhito.

Surprisingly the program works too well and now Tatsuhito has to fend off the advances of his relatives.