CG/l stands for 'Caregiver / little', and is a gender-neutral catch-all term for many of the relationship dynamics found under a certain portion of the ageplay umbrella. Perhaps the most widely discussed of these dynamics is DD/lg (Daddy Dom/little girl), but all possible variations exist and identifying as a caregiver or a little is not bound by sexual orientation or gender identity!
Some people enjoy incorporating the accoutrements of being 'little' into their play, such as pacifiers or colouring books or childlike clothing. Others simply enjoy the dynamic and fantasy, without wanting so much to express their littleness outwardly.
CG/l sometimes comes alongside AB/DL, but there are significant differences between the two communities and the fetishes are not quite the same thing!
AB/DL stands for 'adult baby/diaper lover', and is distinct from other age play fetishes like daddy dom/little girl in several ways. While people who identify as littles often feel as though their 'little self' is an integral part of them, adult babies tend to have a clearer sense of engaging in a role play scenario. Diaper fetishes can also exist in isolation from baby play, and some find it difficult to achieve sexual satisfaction unless a diaper is involved, for example through diaper bondage.
Baby play specifically addresses the natural need of all people to feel loved, protected and cared for - as well as giving its participants the chance to cut loose, relax and give up all their responsibilities for the length of a scene.