[ToPhrESH]

Create a variable:

pawn Код:

new IsPiss[MAX_PLAYERS];

pawn Код:

public OnPlayerCommandText(playerid, cmdtext[])
{
    if (strcmp("/piss", cmdtext, true, 10) == 0)
    {
        ApplyAnimation(playerid, "PAULNMAC", "Piss_loop", 4.0, 1, 1, 1, 1, 0);
                          IsPiss[playerid] = 1
        return 1;
    }
    return 0;
}

pawn Код:

public OnPlayerKeyStateChange(playerid, newkeys, oldkeys)
{
     if ((newkeys & KEY_FIRE) && !(oldkeys & KEY_FIRE))
     {
           if(IsPiss[playerid] == 1)
           {
               ClearAnimations(playerid);
           }
     }                 
return 1;
}

Will this work?