You gotta love Flash for always believing in Spidey.
Amazing Spider-Man (Vol. 1) #17
Published: c. August, 1964?
Cover Date: October, 1964
“The Return of the Green Goblin!”
Writer: Stan Lee
Artist: Steve Ditko
Inker: Steve Ditko
Letterer: Sam Rosen
And in the next panel, he calls Peter “Penis Parker”.