Who or what is a Harvey Wallbanger?

Sassy, Elderly gentleman, was he?

Sassy, After having a few to many of these, I started calling them Henry kneeknocker's

I haven't seen one of those tall thin bottles of Galliano in many years. They're a very unique shape.

I remember a neighbor mentioning it when I was 13yrs old back in the 70s. He said l have a hole in my wall because one night I had a Harvey wallbanger.