Why should we not use our mouths to provide suction for pipettes?
It would be wrong.
A cap either screws on or snaps on and is not flexible, meaning it cannot be used to create suction and draw a liquid out of a container, such as a test tube. A bulb is flexible and can be used to create suction and draw a liquid out of a container.
Well, it is a bit of a safety breach, and potentially hazardous.
I have heard of people who work in biological labs sucking up hepatitis cultures back in the day, when we used our mouths to provide the suction for a pipette (this was not so much an issue in a chemical lab). These days, we would routinely use a
Can you see where the legs might grow? I can't, but these things do tend to disappear in laboratories.
I use to keep these things in the pockets of my lab coat: