AskToSend displays a popup before sending and SMS or Mail Message, and simply asks you to confirm sending the message. For E-Mails, you can configure the tweak to confirm sending any E-Mails with no subject. The tweak was developed by Hanene Samara, who is the wife of evad3rs member pimskeks.
Ask before sending an SMS or Mail message. No more accidentally sent incomplete messages! Very likely this happened to you at least once. This tweak helps you avoiding that. If you tap the 'Send' button in Messages or Mail, it will display a confirmation dialog asking you if you really want to send the message. For Mail, it also has an option to remind you if you didn't type in a subject.
This tweak directly integrates into Messages and Mail, and is configurable via Preferences.
You can grab the tweak from the Cydia Store for $1.99 (BigBoss Repo).