Doctor Feelgood

All the while I was making that cake I was singing 'let's go bake a cake' in my head to the tune of 'let's go fly a kite' from Mary Poppins. Which reminds me of how, back in the day, I used to sing 'tangerine' to the tune of 'Vindaloo' (by Fat Les, natch) to myself everytime I ate a tangerine (or clementine or nectarine). For the entire time I was eating it.

What is that called? There's a medical term for it right?