This term refers to an outing of 3 or more girls. In its extended form it is called a "vagina pageant". It can be related to the term sussage fest (the gathering and hanging out of only men). Note: a vajpaj includes girls and girls only, for you flambouyant homosexual kids (you know who you are) who prefer to hang out with girls, you ruin the vajpaj and make it awkward for people that just met you.
MAN 1: "yo bro we mackin on thoes breezys from franklin tonight?"
MAN 2: " na son they're having a vajpaj."
MAN 3: " my life is a joke let's touch weeners.."