Dildo no Tsukumogami

Seiji is the heir to a unique shrine that has worshipped a male phallic symbol, or “Harigata,” as its deity for generations. However, every time he sees the sacred artifact, an inexplicable heat stirs within him. Unable to endure the frustration, Seiji secretly orders a dildo online to take matters into his own hands. One fateful night, just as Seiji is about to use his new purchase, an incredibly handsome man suddenly appears from the Harigata! The stranger introduces himself as Kanamara, the spirit of the divine artifact. “You don’t need something like that. Use me instead,” Kanamara declares, shamelessly groping Seiji’s chest...?

(Source: Futabasha, translated)

Note: Includes one extra chapter.