According to the font of knowledge that is Urban Dictionary:oh my fucking god. wtf is littlespace. no actually don't search that term on twitter
Littlespace is a mindset in which an adult relaxes into a state of carefree, responsibility-free safety. It may be a developed time in which an adult relives childhood memories, scenarios, or desires that were unachievable in their adolescence. An adult in littlespace may involve another adult referred to as a caregiver, engage in activities viewed as childish, and some may even participate in adult sexual interaction during their time in littlespace. While in littlespace, the adult is usually, but not always, referred to as an adult baby, little, or middle. A standard that all people interacting and involved in this type of scene is that they are all of legal adult age.
I can always count on my Daddy when I go into littlespace to care for me like the little I am.