Desfasan

[Perikles]

Miles de jóvenes británicos desfasan y se emborrachan en Salou

The word 'desfasan' is not in my dictionary.

Link to news item

[poli]

Peri, I think it's a typo. It should be disfrazan.
That's quaint. They they get dressed up in frocks.

[Perikles]

I watched the video and didn't notice that some had fancy dress - they hardly had any clothes at all. But in the written report they mention fancy dress, so you must be right.

[Elaina]

Could it be "deface"?

[aleCcowaN]

Desfase, desafasaje and desfasar should be in any dictionary. This for the main meaning: I, II

The figurative sense is that of I.2., but in Spain it is also a colloquial term for "enjoying until it hurts", "having extreme fun" or something like that.

[Luna Azul]

The verb "desfasar" exists. It means "to get out of phase".

Also, according to the DRAE "desfasarse" (pronominal) means

Dicho de una persona o de una cosa: No ajustarse ni adaptarse a las circunstancias, corrientes o condiciones del momento.

If it were "disfrazar" it would also be pronominal so they would say "se disfrazan".

Alec's explanation sounds good to me, it may be one of those localisms. I had never heard it said with that intended meaning, though.