[Freak_NL]

To larp as a verb applied to a discussion that is not about actual LARP activities (the primary sense of this word) carries a strong connotation of rudeness.

Etymologically it probably emerged in the infamous *chan-culture, and is in active use there in the sense of ‘pretend play’ or ‘on-line role-playing’. It can be used to signal, in a derogatory way, that you feel that the other is spinning a yarn or indulging in a fantasy, without declaring the fictive nature of their comments, in order to provoke responses and bait others into participating.

I wouldn't use this word in polite conversation, unless you are actually talking about live action role-playing.