"Spankable boobs" is a tag used in porn videos that refers to the female breasts being considered as something that can be playfully or sexually spanked. In this context, the term "spankable" suggests that the act of spanking the breasts is part of the sexual pleasure for either the person giving or receiving the action. This tag is used to help viewers find videos featuring such content, catering specifically to those who enjoy this specific form of sexual play in their adult entertainment.