Have you ever hit send on a text message and immediately regret doing so? Maybe the message wasn't complete, or perhaps it was addressed to the wrong person or people, or auto-correct had mis-corrected a word or two?
If you have an iPhone, your options are somewhat limited to how fast you are.
The trick is to kill the Internet connection as quickly as possible before the message can successfully send, and because iPhones have both Wi-Fi and cellular data capabilities available for getting data in and out, your best bet is to get Airplane Mode enabled as quickly as possible after sending the message.
To perform this method:
Step 1: While the message is still sending, swipe up from the bottom of the home screen and then launch Control Center. You might find that it was quicker to close the Messages app before swiping up to get to the Control Center as the iPhone may register swipes as tapping on the spacebar or another key in the bottom row of the keyboard on messages.
Step 2: Quickly tap on Airplane Mode before the progress bar reaches the right side of the screen.
Step 3: Dismiss the message telling you about how Airplane Mode needs to be turned off to send messages.
Step 4: A red “Not Delivered” indicator should appear on the message if you were fast enough.
Step 5: Remove the message from the conversation thread by tapping and holding on the message bubble and choosing More > Delete.
Step 6: Re-enable Wi-Fi and cellular data by turning Airplane Mode back on.
For an Android phone, you options are better. Many times, the phone itself has an option under Settings that will allow you to add a delay to the sending of the message. If it does, set it for 5 seconds so once you press "send" you'll have 5 seconds to stop the message from going out.
If your phone doesn't give you that option, you can use an app, such as ChompSMS. ChompSMS allows you to customize your messaging app on your phone. You can vary the look of the app, set delay time limits, install themes, add pictures to your contacts and much more. The free version displays an ad at the top of the messages but the paid version, which is $2.69, removes that ad. For me, being able to stop a message from sending is well worth it.