With a quick wish, you do several things:
1: Only you, the barista, and the boys would realize what was happening.
2: The boys would be trapped in their own bodies. Anything they did would be filtered through their personalities.
3: They would all become cowgirls of various degrees. The smallest one will be an Amazonian Minotaur girl, the middle two will become twins, and the tallest one will just become a big breasted, lactating woman. You're not a monster, however, so they'll transform back if they want the next time they sleep.
As they're laughing about something, they suddenly start changing dramatically. All except the minotaur look horrified, he, now she most likely, looks overjoyed, before their personalities start overriding. The twins both head up and walk over to one of the jocks from school, Tim you think. 5 minutes later, he's walking out with both hanging on his arms. You make sure they'll wake up in their own beds, just in case. You lock eyes with the minotaur as she walks out, followed shortly by the lactating one.
You finish your coffee, before sing-songing 'you're welcome!' to the barista.