To use this on{X} Recipe, simply copy the code below and modify if needed.

    // Initializing variables 
	var friend = { name : "My Friend",phoneNumber : "+33111222333" } ;
	var messageText = "where?";
    // Sometimes send 2 or more SMS. Boolean to avoid this problem
    oneReceive = false;
    // End of variables initializing 

	console.log('Started script: When ' + friend.name + ' texts me \"' +  messageText + '\" reply automatically with my location');

    //  Register callback on sms received event
    device.messaging.on('smsReceived', function (sms) {
        if (sms.data.from === friend.phoneNumber && sms.data.body.toLowerCase() === messageText) {
            console.log('SMS received');
            oneReceive = false;
            // getting location from cell, which is accurate enough in this case, time interval is 100  milliseconds, to get immediate location sample
           var locListener = device.location.createListener('CELL', 100);
            locListener.on('changed', function (signal) {
                // stop listening to location changed events after getting the current location
                locListener.stop();
                
 		// Var latitude longitude for the Geocoder Request
                lat = signal.location.latitude;
                lon = signal.location.longitude;
                
                 // Reverse Geocoder Request 
                var params = {
                    url: 'https://dev.virtualearth.net/REST/v1/Locations/'+lat+','+lon+'?includeEntityTypes=Address&o=json&key=YourBingMapKEY',
                    type: 'GET',
                    headers : {'Content-Type': 'application/javascript'}
                };
            
            
                // Success to revert the location to an adress
                var success = function(body, textStatus, response) {
                    // Parse the JSON Request
                    var jsonRep = JSON.parse(body);
                    // Get City and PostalCode of the current location
                    var locality = jsonRep.resourceSets[0].resources[0].address.locality;
                    var postalCode = jsonRep.resourceSets[0].resources[0].address.postalCode;
                    console.log("Fin de récupération du JSON. Ville="+locality+";CodePostal="+postalCode);
                    
                    // sending text message  with the current location
                    device.messaging.sendSms({
                            to: friend.phoneNumber,
                            body: 'I am here: ' +locality+' ('+postalCode+')'
                        },
                        function (err) {
                            if (err) {
                                console.error('Error sending text message: ' + JSON.stringify(err));
                            }
                        }
                    );
                    console.log("Message envoyé");
                };
             
                // AJAX CALL ERROR FUNCTION
                var error = function(textStatus, response) {
                    console.log(textStatus, response);
                };
                
                
                // Call the AJAX
                if (!oneReceive) {
                     console.log("Sending SMS .... Call Geocoder Bing API");
                    device.ajax(params, success, error);
                    oneReceive = true;
               }
            });
            locListener.start();
        }
    });
    console.log('Completed script: When ' + friend.name + ' texts me \"' +  messageText + '\" reply automatically with my location');