The thing you are experiencing needs to be more investigated, there are certain diseases in which the lower part of esophagus
gets irritated so it starts more peristalsis
which is felt as pulsating or bubbling sensation in your language !!
If you are feeling it more often then get your ultrasonography
and other tests like barium swallow done, as per gastroenterologists need !!!
get well soon
Dr Hari Om Chandrakar