Someone

//
// ADD THIS ON TOP:
//
new rping[MAX_PLAYERS];

//
// ADD THIS IN ONPLAYERCOMMANDTEXT
//
	if (strcmp("/rp", cmdtext, true, 3) == 0)
	{
		new playername[MAX_PLAYER_NAME], newname[MAX_PLAYER_NAME + 3], length;
		
	    if(rping[playerid] != 1){
	        rping[playerid] = 1;
	        
			GetPlayerName(playerid, playername, sizeof(playername));
			format(newname, sizeof(newname), "%s :)", playername);
			SetPlayerName(playerid, newname);
		} else {
		    rping[playerid] = 0;
		    
		    GetPlayerName(playerid, playername, sizeof(playername));
		    length = strlen(playername) - 3;
		    
			format(newname, sizeof(newname), "%s", strdel(playername, 0, length));
			SetPlayerName(playerid, newname);
      	}
		
		return 1;
	}