They often have many friends who are douche bags but can not live up to the persons omnidouche status.
An omnidouche is noticeably different from a regular douche bag only during said events where they still try to act cool and stupid even though it is not the time.
Omnidouche comes from the words
<omni - infinitely> and <douche - female genitals>
guy:That guy Luca went to his wedding in jeans and a pink polo. he's such an omnidouche
omnidouche:Hey guys guess what I just had sex with that girl once and I'm not going to marry her even though she's pregnant. Who wants an unprotected all night orgy?