Desire follows on (anujanma) pleasure
When one familiar with a pleasure now has a memory of it, his eagerness for the pleasure or for the means to it, that thirst or greed, is (called) desire.
Desire follows on (anujanma) is the consequence of (anuśayī) pleasure. To follow on means to arise afterwards. There are other readings of this sūtra and the next as ‘the consequence (anuśayī) of pleasure’ and ‘the consequence of pain’. They read the sūtras as Desire is the consequence of pleasure and hate is the consequence of pain, meaning that the character of the one is to be a consequence of pleasure, and similarly with pain. In both readings the sense is simply following on, and that is its habitual character. So he will say, ‘From righteousness, pleasure; from pleasure, desire’ (comm. to IV.11).
As to the nature of this following on, he explains: When one familiar with a pleasure, knowing about it, now has a memory of the pleasure recalling previous experience of it, his eagerness for the pleasure the thrill or the means to it, in the shape of addiction to aloes and sandal and so on, that thirst or greed, is desire.