when you take the physical aspect of a relationship wayy to fast (skipping bases). knowing that its not a good idea. generally happening the 1st week of a relationship or the 2nd day. doing this results in turning the relationship into a relationshit.
jasmine: did you hear? mike and koral totally 2nd day'ed their relationship yesterday.
sammy: wow. what fools. well, i hope they have luck with the rest of their relationshit.