To help move past those destructive urges
Urge Surfing is an aspect of Mindfulness and can help us to sit with those destructive feelings and overcome them.
There are a few tips and techniques you can use to ride those waves, and Urge Surfing with Mindfulness is one of them. Another good one is the method of 'putting it off'. Let's say you have an urge to self harm. Instead of saying "I must not do it!" and giving in under the pressure, say to yourself "I will allow myself to self harm, but not until 10 minutes is up". Once those 10 minutes are up, you may find that the urge has passed. If it still hasn't, try and go for another 10 minutes. You can adjust the times according to how badly you feel you need to do it. Sometimes you only need 1 minute to get your thoughts together! And it's ok if you do eventually cave in - just try again next time, and you may find that you're able to hang on for a bit longer each time.