From what I understand peoples experiences can vary. I have experienced 4 different types of formats but never anything physical to do with the ajna chakra that I was ever aware of…
1st Type is…I lay flat on my back. I choose darkness in room. I close my eyes drawing them inwards, very slightly boss eyed. I find laying flat aligns my focus down the length of my nose to the tip. I then look into the blackness in that direction, for a light, a tiny yellowy white light. When I spot it I try and hold onto it, it comes and goes I keep looking for it and so on. At some point it gets bigger, this is the third eye opening. I’m then aware of speed and travelling in a light sort of tunnel. and then I see whatever Im presented with.
2nd Type …This format is more easy, I do all the same as above except I start to see a blue/violet light, not a pinpoint yeloowy/white light. By keeping focus on it, it begins to fill the space im viewing. I then see a hole appearing in the blue, I focus on the hole, it gets bigger and then this is the third eye opening to a scene
3rd Type…This in is a relaxed, meditative state that can happen anywhere anytime any position but usually laying on my side. Im presented with a full colour bright colour scene, Hindu/Buddhist in its representation, triggered sometimes by a thought accidentally thought by not realising I am in this state. Or jst presented without any thought.
4th type…this is the most important. The red heart, referred to by Buddhists. This is a format of red and black intertwining streaks, moving at a steady pace a definate feeling of a steady journey ahead . The scene draws to a sto and there ahead of you to the left or right is a seated Buddha. You think then, quite naturally…what or who is that, there isnt any fear in you…u move closer to him and after a while he wakes and levitates and moves central to your eye positioning and moves into the brow area.
These are my experiences, I hadnt noted any physical feelings because my focus is only on the light and nothing else. It helps if your body is very tired because body focus is less.