Biological fluid collection. At least some of the illustrative embodiments are systems including a sleeve of elastomeric material and a receptacle coupled to the sleeve. The sleeve may include: first and second ends, each end comprising respectively a first and a second orifice and a passage extending between the first and second orifices. The receptacle may include: a side wall and a bottom that define an interior volume and a height and an entrance portion that defines an internal diameter, wherein the height of receptacle is at least half the internal diameter. The receptacle may mechanically couple to the sleeve such that the interior volume is fluidly coupled to the passage of the sleeve.
