a person who is far more douchebaggedy than your everday douche bag. That word is insufficient, which warrants the use of douche cannon, when this person is off the charts in douchebaggedness scale, and you would readily render them infertile using acid on their genitalia. Douche cannon originates from the early name calling methods used during the Revolutionary war era. British soldiers commonly degraded their fellow army members, when they were incompetent with a cannon or other gunpowder apparati, They were aptly named "douche cannons" and usually were subject to sodomy from their horse. In conclusion, this is the strongest level of douchebaggery, use it wisely for its conotations are far more powerfull than calling someone a fag, or retard, or shitbrick.
Speaker A- Dude my mom's a complete douche cannon
Speaker B- WTF i can't believe you just called your mom a douche cannon, thats serious shit