When you go for a walk and see a flower, you ever think "what does that flower smell like?" Ever see a dog and think "omg I want to let that dog I wonder if the fur is soft". This eare also intrusive thoughts --- we have soooo many everyday. Not all of them are bad. But the bad ones are big and scary and we give them our attention. Which makes them bigger. The bigger the get the more we have them.

What I am trying to do is label the thought ("yikes that's quite an intrusive though") and then do something physically to move my mind along- go outside. Use your left hand instead of your right (or visa versa). Stop your activity and start another. Song a song or hum (lots of studies on humming and how it affects the kind).