Dave and Hannah have been dating for a long time

One day, Hannah says:

'If you come to ours tomorrow evening for dinner, I'll give you my virginity.'

Obviously, Dave is very happy about the idea and says yes. That very night, after walking Hannah home, he enters a pharmacy, buys condoms and asks all kinds of useful questions about sex and other stuff from the pharmacist who patiently explains everything he needs to know to Dave.

The next evening when he arrives to Hannah's, the girl's parents are already sitting at the table. Once the young couple joins them, Dave looks around for a moment, then asks whether he could say grace. Dave prays for a very long time, bowing his head, with his eyes closed. After this goes on for 20 minutes and not a single word is uttered for that same time, Hannah whispers to Dave:

'I didn't know you were so religious.'

To which Dave replies:

'Yeah well, I didn't know that your dad was the pharmacist...'