To engage in a romantic relationship with a person who is much better looking, and/or smarter, and/or in a higher socioeconomic class than you. Essentially, a person who is widely considered to be 'out of your league.'
Bob: Your new girlfriend is smokin' hot... A legitimate '8'... How do you continue to keep outkicking your coverage.
Other guy, also named Bob: I have an extremely large penis!
To have a bigger penis than others, to Out-Do somebody in that area. Applied when the outdicker is younger, or of a race not expected to be bigger than the outdicked.
Verb: in homo sapiens species, when two males compete over a female through sperm competition, the higher ranking male and consequently the winner of the seduction process is said to have outdicked the lower ranking male, aka he has a bigger dick.
Beta male: WTF? That kid is all over your girlfriend bro, why don’t you beat his ass right now.
Alpha male: let him have her and she’ll come back crying to be with me again in less than a week. I can outdick the shit out of that noob anytime.