Sorry but rules forbid when airborne.
Instead in flight request a visit by asking one of the cabin crew if you may do so on the ground once in Malaga. Be the last people off and you stand a good chance of having a look-in subject to considerations such as time, your appearance and any training taking place on that trip. Plus don't drink.
You can try the same on the way home. It should work on at least one leg.
Good luck,
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