Similar to the phrase that someone's "eyes are bigger than his/her stomach," which means that someone overestimated the amount of food that he/she wanted, having eyes bigger than one's vagina means that someone overestimated the size pecker (wanker, johnson, peter) that she wanted or could handle.
Girl 1: "How was your sleepover with George last night?"
Girl 2: "I'm still sore!"
Girl 1: "Ha, I guess your eyes are bigger than your vagina!"
(Girl 1 is an example of someone who has eyes bigger than one'svagina)
An eye-jam is a staring contest on steroids. Two combatants, usually dom and craig, lock into a dead stare into the depths of each others irises. Winner is determined by the first person to blink, look away or smile. While seeming mundane in its nature, excessive and/or extreme, perhaps even backwards, eye-jams can lead to deterioration of sight, lack of ability to see color, loss of depth perception, low self esteem (if youre dom), extreme gayness (again, if youre dom) and in some worst case scenarios, even paralysis or death.
Dom couldnt eye-jam his way out of a wet paper bag.