Usually only occurs whilst on strong anti-biotics and a vegan diet. A 'salad blender' is the undigested reminants of sald, left over in a stool. Though it is essentially excremant, it still fully resembles salad and has many health benifits if consumed.
Example 1:
Hey Matty! I left a steaming SALAD BLENDER in the toilet, come check it out.
Example 2:
That chick, Jane, is a huge bitch. Let's feed her one of my SALAD BLENDERs and say it's a falafel.
Example 3:
You should get those SALAD BLENDERs checked out, Jim. They are staining the toilets.