The old man takes the old lady to the doctor for a checkup.
The doctor wants to have some fun with the old man so after the checkup he tells the old man
that the problem is serious the old ladies health is deteriorating and the only cure is sex.
The old man says "Sex?"
"Yes", the doctor says "Sex, you know."
"How many times must she have sex?"
The doctor says "Three times a week."
"What days?" the old man says.
"Well, lets say Tuesday, Thursday and Saturday."
"Well, doctor, Tuesday and Thursday is OK, but on Saturday I have golf, so she will have to catch the bus to come and see you."