Deutsche Grossmutter tells a story (translated)

Professor Wonderful, a very skilled person, gives a lecture about the heart: The expression heart is completely wrong he speaks out loud and wild, it should be called pump and I want you to call it pump from now on!
Cause it pumps like a pump the blood in a circle and so it should be called pump also by science.
The students listened very carefully, but he only explained the pump and forgot about the heart.
Suddenly one student jumped up and shouted: Dear honored Professor, this is not O.K, when you are in Love and feel hot desire, how can you say then: Oh my sweetheart my pump is aching, come to my pump my sweetpump, oh can't you hear my pump crying for you?
The professor hesitates, as the student ends his speech, the whole classroom is laughing. Now he shouted: Are you kidding me? Just let's return to the good old heart!

and still driving!
(please take your time to find her)