Dad caught me

I am 18 years old and still live at home and ran into sort of a problem
last night. I was in my bedroom with my door closed wacking off when my
dad walked in just as I was ready to lose my load and I felt kind of
strange but got to that point where I didn't care as long I got to finish
and cum. My dad stayed in the doorway and watched until I was done.
After I shot he said, "WOW!" and walked out of the room!

Has anyone ever had anything like this happen to them before and what
would you have done?