Examples:

• He always shoots off his mouth without thinking, and it often gets him into trouble.
• I told him not to shoot off his mouth about the surprise party; now everyone knows!
• The politician tends to shoot off his mouth during interviews, making controversial statements.
• Don't pay attention to him; he likes to shoot off his mouth and exaggerate things.
• She couldn't keep a secret and ended up shooting off her mouth about the surprise vacation.
• The gossip columnist is known for shooting off his mouth and spreading rumors.
• When he's angry, he tends to shoot off his mouth and say hurtful things.
• The team captain reminded everyone not to shoot off their mouths to the press before the big game.
• I was careful not to shoot off my mouth about the job offer until everything was finalized.
• He regretted shooting off his mouth and making promises he couldn't keep.