Point blank - if a girl is interested, username isnt going to turn them off of you(unless its like.... JizzOnYou2 or something similarly creepy) And if a girl isnt interested, shes not going to magically like you because of your username...so just pick something that you like. Why not "Money_Shot" ?
The Pain of Discipline, or The Pain of Regret. Take Your Pick.
*You either have the things you want, or the reasons why not*