toe-curling 
adjective informal
Very embarrassing or excessively sentimental: a toe-curling ballad...
- The self-satisfaction and smugness of the text is toe-curling and its frequent sickening doses of sentimentality are like being forced-fed chopped liver with chicken fat.
- This is an approximation, the original was even more toe-curling, if you can believe it.
- When we catch up on the phone it's to discuss her latest short-lived conquest, the details of which are usually colourful, sometimes toe-curling and always entertaining.
Derivatives
toe-curlingly
- Can we make it really toe-curlingly embarrassing?
- Firstly, why would anybody want to read this sort of toe-curlingly painful stuff for any sustained period of time?
- Most official England anthems are toe-curlingly dreadful while the pre-match piped music at football matches isn't much better.