In the midst of slamming a girl doggie style, when she least expects it, you pull out and shove your pecker dick in her asshole, only to achieve just the tip (hence the belgium midget) before she donkey kicks you in the chest. Because truly, "Oops wrong hole" is not an accident...
Katie B: That ma-fucka Tyrone attempted to try the Belgium Midget again last night!
Shaniqua: Doesn't he know, there is no oops wrong hole?...Did you donkey kick his Ra-Tard ass?
Katie B: Fo sho....he won't be trying the Belgium Midget fo awhile...