Primal play in the kink context as getting to a place where the masks civilization can fall away and to allow acting on urges and impulses more directly.
These can be raw, rough sexual feelings, but they could also be joy, silliness, deep feelings of love and intimacy, feelings of deep tenderness, even sadness and grief.
“Primal” doesn’t necessarily have to mean “rough” (though it often may); it’s more a matter of being raw and unfiltered, whatever the feelings present are.
It is important to note that intentionally evoking raw and unfiltered emotions and reactions can sometimes lead to increased safety risks (emotionally and physically) due to loss of self control. Because of this potential, some may consider primal play to be a form of edge play.