It’s quite interesting how we aren’t able to recall the exact moment when we entered a dream or when we enter a trance (which is “absorption” or “the flow”).
The same goes for thought in conjunction with its projections and emotional intensity. The moment when thought appears, that is when attention is absorbed by it. However, by remaining still psychologically, one can consciously withdraw from thought construction just a slight moment after being absorbed by it.
School of In'Sight 