 There are some ways to know that you activate your pineal gland, first of all your vision becomes clearer. If you close your eyes you may see a haze of white light. Another symptom of opening your pineal gland is that you hear this hissing noise. This is something that actually feels good. It feels like you've expanded your hearing. You can actually hear more. It's actually connecting from outside, coming from inside your body. Third way to know is you have more saliva. Some people say it tastes sweet. That's another sign that you've activated your pineal gland. Another way is you feel tingly in your head, especially in the crown and the temples. Another way to know is that you feel like you're standing up straight or you feel like your spine is lengthening and elongating. You feel like there's this kind of invisible force pulling you from the top of your head, lifting you up and straightening up your spine. So those are some of the physical things that you've experienced when you open your third eye or activate your pineal gland.