With Ambaṭṭha 2.18.9

2.18.9

Atha kho bhagavā tathārūpaṃ iddhābhisaṅkhāraṃ abhisaṅkhāsi yathā addasa brāhmaṇo pokkharasāti bhagavato kosohitaṃ vatthaguyhaṃ.

Then the Buddha used his psychic power to will that Pokkharasāti would see his private parts sheathed in a foreskin.