Germany finds out that Italy fantasizes about being taken rough and hard. Germany wants to be able to do this for him, but any time he tries, he has terrifying flashbacks to hurting Italy during WWII (either sexually or just physically). Italy's not scared of him, but Germany can't get past it.
Germany doesn't want to stand in the way of Italy's fantasy, so he brings in the only person who he trusts enough to do this for Italy - Prussia.
Bonus 1: using human names Bonus 2: Prussia is really into the idea, but only after making sure both Italy and Germany are cool with it Bonus 3: Germany watches the whole thing and loves it, and helps him get past his fear of hurting Italy. Up to you whether or not this becomes GerPruIta, but as long as Italy is getting plenty of loving I'm happy Bonus 4: Prussia has at least one moment of being really gentle with Italy because he can't help himself
PruIta - Germany wants Prussia to give Italy what he can't
Germany doesn't want to stand in the way of Italy's fantasy, so he brings in the only person who he trusts enough to do this for Italy - Prussia.
Bonus 1: using human names
Bonus 2: Prussia is really into the idea, but only after making sure both Italy and Germany are cool with it
Bonus 3: Germany watches the whole thing and loves it, and helps him get past his fear of hurting Italy. Up to you whether or not this becomes GerPruIta, but as long as Italy is getting plenty of loving I'm happy
Bonus 4: Prussia has at least one moment of being really gentle with Italy because he can't help himself