The invention in one of its aspects provides a connection apparatus for a subsea hydraulic circuit and method of use in a sampling application. The apparatus comprises a longitudinal body configured to be removably docked with a subsea hydraulic circuit receptacle. The body comprises a plurality of radial ports axially displaced along the body, and an axial bore accommodating a spool having at least one fluid barrier. The spool and fluid barrier are actuable to be axially moved in the bore to control axial flow paths along the bore between the plurality of radial ports. The apparatus may be configured as a sampling hot stab in an application to sampling a production fluid from a subsea hydrocarbon production system.