A very old guy visits a doctor specializing in sexual dysfunctions:

- You know doc, says the old guy, I have met a a girl about 20 years old and she and I... you know, I have a problem but I am not very comfortable to talk about it...
- Do not fear me, says the doctor, what's the problem, aren't we men after all?
- Ok, says the old man, you know, she likes me and I can see that and I have tried to be with her as many times as I can, but you know, there is this problem...
- Come on man, says the doctor, tell me about the problem.
- Well, says the old man, the first poses no problem at all, but in the second I start to pant heavily, and by the third... oh sweet God, my heart is pounding so hard, feels like it's breaking up and I cannot keep up any more....please help me....I want you to give me something....
- Wait a minute, says the astonished doctor, how old are you?
- I am 93 years old this February, replies the old man.
- Well, I am proud of you my friend, smiles the doctor, at such an old age and you manage to keep up till the third, even I can't do that and I am 40 years younger, I don't see that as a problem at all...
- But you don't understand, says the old man, you must help me, the little slut lives on the fourth floor....