Please explain this German "DDR" joke to me.

Too good an opportunity to pass up a joke relying on German accents.

German man walks into a pharmacy. Says ‘hello, I would like to buy some deodorant’.

Pharmacist says ‘certainly sir. Ball or aerosol?’

German: ‘Neither. I would like it for my armpit.’

I don’t get it. What’s the German accent angle?

It may not even work in American, but it’s a treat in English English.

The pharmacist’s pronunciation of ‘aerosol’ is similar to the German’s pronunciation of ‘arsehole’.

You can laugh now.