Answer :
In this case, you are using a simile.
"Being in bed is as relaxing as one can get" would be a great simile to use.
Changing it to "as" is still called a simile but making it even better.
"Being in bed is as relaxing as one can get" would be a great simile to use.
Changing it to "as" is still called a simile but making it even better.