yadagre chaanubandhe cha sukham mohanamaatmanaha |
nidraalasyapramaadottham tattaamasamudaahritam || 39 ||

That which deludes the self initially and in its result, caused by sleep, lethargy and intoxication, that joy is called taamasic.
yat : that which
agre : initially
cha : and
anubandhe : in its result
cha : and
sukham : joy
mohanam : deludes
aatmanaha : self
nidraalasyapramaadottham : caused by sleep, lethargy and intoxication
tat : that
taamasam : taamasic
udaahritam : is called
There are some people in this world for whom even ten hours of sleep is not enough. Some others do not want to start any task unless they are reminded several times. Or even worse, some people constantly seek alcohol, smoking or drugs. There has to be a reason why people gravitate to such methods. They derive joy, happiness and a sense of pleasure in these things, even if they know that they will lead to social, physical and mental ruin in the long run. Such a kind of joy is called taamasic sukha.
Shri Krishna says that such people are in moha. They are deluded into thinking that the state of stupor, created by indulging in excessive sleep, laziness and intoxication, is happiness. In other words, there is some sensation of joy which has to be acknowledged, but it is unwanted and destructive. Worse still, this perverse type of joy remains throughout the beginning, middle and end of the action. A lazy person will remain comfortably situated in his stupor throughout the day, and continue in his stupor through sleep in the night.
If we examine our lives, we may see that there are a few moments where we may sink into partaking taamasic joy. It is next to impossible to come out of this state once we are in it. Once someone has had a high quantity of alcohol, for instance, there is no way for them to recover. They just have to wait for it to leave the body naturally. Short of keeping a high level of awareness towards what we eat, drink, watch and think about, there is no clear antidote for taamasic joy.