For some people grounding techniques may work. These usually stimulate your senses to keep you in the present moment. You can find a list of techniques here
When I get triggered it is usually because my inner child has connected something present with the past and become very frightened or anxious. I find any technique you might use to comfort a frightened child helps me including cuddling a favourite soft toy (if you haven’t got one it is fun to go and liberate one from a charity shop), being wrapped in a soft and cuddly blanket (I have a pink one I keep specially), drawing or scribbling with wax crayons (crayons take me straight to my childhood, even just the smell of them)-let your inner little person express themselves with no judgement from you, it doesn’t have to look nice!
I have also posted some lullabyes that I find soothing here
A comfort box-I have never actually made one of these but I think I would like to. I like the idea of decorating it and also maybe writing notes to myself to put in it.
Sometimes the only way out is through. When all else fails I find ways to express how I feel. Some of what works for me is editing photos on my computer, creating a photomanipulation to express my feelings or portray a scene from the past, making an art journal page, writing poetry.
Let yourself cry
I know a lot of people find it very difficult to cry. I have been researching crying and it is an amazing release of stress both physically and mentally. Research done on tears from emotional crying show that they contain stress hormones. This is helping to protect our brains from the harmful effects of a build up of these hormones. Isn’t that amazing?
Listening to sad music or watching a sad film can give us permission to cry.
If you have any techniques that work for you that I haven’t mentioned here please feel free to comment.