A young man goes into a pharmacy and tells the pharmacist, " I'd like a condom. My girlfriend has invited me for dinner and I think she is expecting something from me!"

The pharmacist gives him the condom. As the young man is almost to the door, he does an about face and returns to the counter.

"Give me another condom," he says. "My girlfriend's sister is very cute too. She always crosses her legs really sexy when she sees me and I think she might be looking for some action, too."

The pharmacist gives him a second condom. Once more as the boy is leaving, he turns back.

"I'd better get one more. My girlfriend's mom is pretty hot, too. When she sees me she always makes allusions... and since she invited me for dinner, I think she might be looking for some, too!"

During dinner, the young man is sitting with his girlfriend on his left, the sister on his right, and the mom facing him. When the dad arrives, the boy lowers his head and starts praying.

"Dear Lord, bless this dinner. Thank you for all you give us...."

A minute later the boy is still praying. "Thank you Lord for your kindness...."

Ten minutes later, and the boy is still praying, keeping his head down.

The others look at each other, surprised and exasperated. His girlfriend leans over and whispers in his ear, "I didn't know you were so religious!"

The boy responds, "I didn't know your dad was a pharmacist!"
I can explain it to you but I can't understand it for you.