The bardo of meditative absorption may be described as the period of time we spend in meditative equipoise. It terminates when we arise from this state.
It is called a bardo because it is not like our ordinary current of deluded thoughts, nor is it like phenomenal perception as experienced in the course of life.
It is a period of meditative stability, a state of concentration as fresh and untarnished as the sky.
It is like a motionless ocean in which there are no waves.
It is impossible to remain in this state when the mind is full of thoughts (appropriately likened to a gang of robbers), or even when it is occupied with more subtle mental undercurrents, mixed and matted together like threads. Stable meditation is impossible in such circumstances.
The teachings say that meditators must not fall under the power of their thoughts, which are like thieves.
They should instead have undistracted mindfulness and powerful diligence with which they can prevent their concentration from disintegrating.
The dream bardo and the bardo of meditative absorption are subdivisions of the present life. The bardo of the present life naturally includes our practice. Even if it is intermittent, it is of necessity performed within the scope of our present existence. It is only here that we can meditate.
Source: Dudjom Rinpoche. Counsels from My Heart (Kindle Locations 739-742). Shambhala Publications. Kindle Edition.