I found a solution on steam but I haven't tried it myself.
Conditions:
1. When a guest enters the cafe, they must be seated at the first table situated at the top left, closest to the bar. Note: If there are no other guests around, the receptionist will always lead the guest to that first table
2. That guest's request must be asking for Jena.
3. On the player's side: instead of assigning Jena; assign another maid to accompany that guest
4. When the new maid picks up the food and attempts to persuade the guest, the persuasion must fail.
5. Afterwards, the guest will be seated alone savoring his lonely meal.
6. Next, summon Jena to the Front
7. Speak to Jena and click the option Lick My A**h*le
8. NTR triggers.
My successful tryouts was when starting a new game entirely. That time both Jena & Gina's PUA was at lowest, making it extremely easy to fail a persuasion... alas, it was not really worth it.
