In the pronunciation of the vowel Ы the bulk of the tongue is retracted from the front teeth while the back of the tongue is raised. The lips are passive, motionless.
Read these vowels. Watch the position of the tongue and the lips.
а - ы а - и - ы а-о-у-ы-и-э-а
а - у -ы а - э - и - ы а-э-и-ы-у-о-а