Bbw4doc there is a correct method for using a stethoscope.
Insert the earpieces so that they point forward towards the bridge of the nose. That will ensure the eartips fill the ear canal allowing for an uninterrupted sound pathway, and a snug aural fit to block outside noise. If you position them backwards, the earpiece will actually rest against the Cymba cavity, obstructing transmission.
This YouTube video shows how you should insert the earpieces.
https://www.youtube.com/watch?v=v1Z7I7guG08
Setting up a stethoscope
https://www.youtube.com/watch?v=gcmaDhLLeJA
Also some tips for using it
https://www.youtube.com/watch?v=L5PPi7hBgWQ
If the fit isn’t comfortable, or acoustic performance is lacking, adjust the headset tension. All stethoscopes feature adjustable headsets. Gently squeeze the eartubes together to increase headset tension; pull them apart to decrease tension. This feature is available for most good quality stethoscope , you may need to look up your particular brand of stethoscope .
Also selecting the best fitting earpiece will help/add to your comfort and also aid the acoustic performance of the stethoscope .
For Littmann Stethoscope , useful tips follow this link :
https://www.3m.co.uk/3M/en_GB/Littmann-UK/my-stethoscope/using-your-stethoscope/usage-tips/
Hope this helps