Microcaps - 795050 1-000-1000 Disposable Glass Micropipettes, 100 uL; 100/Pk

The instructions seemed clear, but I practiced and practiced, and success at being able to dispense exactly 100 ul was sporadic at best. At times, after aspirating an amount of liquid into the micropipette, some of it would appear at the bottom of the small glass tube to which the black rubber bulb is attached, and getting that out was a chore.The instructions say when to do which step, but I found that no matter what I did, immediately after aspirating liquid into the micropipette, the liquid would then begin to run back out. I had to be extremely fast to aspirate liquid, and transfer the micropipette to the approrpiate receiving container to even think I had transferred 100 ul exactly.Wonder what I was doing wrong? And I wonder how the instructions could have been more clear or accurate.