The phrase "tightening sensation" refers to the feeling of something becoming tighter or constricting. It could be a physical sensation, like muscles getting tense, or a metaphorical sensation, like feeling anxious or stressed.
Sentences with «tightening sensation»
How about that backache and slight tightening sensation in your abdomen? (pregnancy-info.net)
These weaker tightening sensations allow the body to prepare for the stronger contractions of labor. (momtricks.com)
If you experience more than four tightening sensations in an hour (to rule out the ris of real labor). (momtricks.com)