pull your punches
pull (one's) punches
1. To act as if one is punching someone, without making any or much physical contact. (Short for "pull one's punches.") How dare you—have never pulled my punches during a fight in my entire career! I know you're trying to make the scene realistic, but please pull your punches next time!
2. By extension, to restrain one's commentary or criticism to avoid offending or upsetting someone. (Usually used in the negative.) I want your honest opinion of my story—don't pull your punches! Wow, your aunt really doesn't pull her punches. Is my sweatshirt really that ugly?