The options used to sleep should be avoided without losing a single time because it does not remember that there is already an opponent pokémon sleeping, as well as taunts in status moves.
I won't even answer anyone who says: but you can look for who's sleeping in the battle diary
edit: when trying a second sleep accidentally i shouldn't miss a shift but a message that this can't happen because there is another pokemon sleeping.
this is reasonable since we cannot clearly see the condition of all the opponent's pokemon, and we cannot cancel an already used move