Nuppunupu Oyako Mix!! ~Double Oyako to Lovelove Pension Seikatsu~

The protagonist, somewhat of an otaku, is looking forward to his "mini-NEET" summer vacation lifestyle when he's recommended for a part time job by a friend. Initially disappointed that he can't kick back and relax and game all summer, he finds his fortunes turned around when he discovers that the job is at a timeshare owned by his friend's glamorous widowed mother. He ends up at the summer house surrounded by a pair of incredibly beautiful and well endowed mothers and daughters, making for all sorts of lovely summer memories.

[From J-List]