Not a text as such, but I did it on my phone so it sort of counts.
A few years ago mid-week morning after a work's night out, I had been texting a couple of friends on my blackberry about a phone being handed over during the evening for colleagues to look at baby pictures and they had swiped a little too far and found some intimate photographs, handed the phone back without telling the owner, and then promptly told me.
I typed out the tale of what had happened, sent it to one friend, then copied, pasted and sent to the second friend. Thought no more about it.
Then, late that evening, I started to look at work emails on my phone. One was urgent and required some technical jargon to be copied and pasted into another email that I had to send to two senior managers in the organisation I worked for - one was the head of technical security.
Something hadn't worked properly and what was actually pasted into the email was the text I had sent to my friends earlier in the day. I started pressing the delete button very quickly when I realised but my blackberry froze part way through and then the email disappeared off the screen! Absolutely aghast, I had to run downstairs, fire up my laptop, connect to the VPN, open my emails, found that the email had sent, recall the message, and then type the correct message with a title that said ignore previous email.
I received two message recall failures and for days afterwards, I lived in terror of being hauled up by my manager about sending such an offensive email to somebody who had a big bee in their bonnet about the security of work emails.
What did it say?
"and in the middle there was a picture of a big black cock going into her arsehole"
Still makes me howl with laughter 