Take a tractor 2″ radiator hose about 2′ long
and a bicycle tire inner tube
Cut out a 3′ section to slide down inside the hose
leaving 6″ out at each end
At one end fold the tube back over the hose
securing it with a rubber band
Do the same at the other end
but before you do
pour some hot water (100 degrees)
between tube and hose
and seal it in as above
Then take your test tube and rubber flange
slide it over one end and secure
Astroglide jelly up the other end
Now you’re ready for the bull
When he goes to mount the cow
slip the rig over his budelia
and Bob’s your uncle