Okay, here's why this isn't funny:
You're trying to make it funny by having saturn give a really unfunny retort. This might normally work, however the reaction of saturn implies that he himself understands that the retort is shit. The humor of the "bad retort" gag is that the retorter actually thinks their retort is witty.
Things are made further unfunny by the fact that the "small dick" is the king of "bad counters used as a bad counter". It's like a "yo momma" joke; Not only is it an overused retort, it's an overused EXAMPLE of an overused retort. Saturn comes across not as a guy who thinks his retort is funny, but as a douche who thinks that using an overused retort is funny.
That's not funny. That's just fucking irritating. He knows his joke is shit, and he tells it anyway.
Oh, and THE PICTURE IS TOO BIG, RESIZE IT YOU FAGGOT.