>>36843272This story is fake and gay, but hypothetically, you should pray that she likes the gijinka/monsterboy versions of these two pokemon. Lots of folks love them some monstergirls and monsterboys with animal-esque genitals, but bestiality still gives them the creeps. If you're lucky, your sister has similar tastes.
Or this is just a fantasy for her and she'd be repulsed by an actual dog's dick just like anyone else.
God willing, this is all just made up, as everything on 4chan is.