Ayin Merash Tanchuma Tchilas parshas " Vayigasg Yehuda" The nekudah of their milchama was that yosef couldn't suffer a fall, as you said, he couldn't stand busha... and he therefor hinted, and kept hinting to his identity, anything to not embarras the shevatim (as did happen). And the busha was SO GREAT "ki nivhalu lifanav" which chazal compare to the great busha when HKB"H comes knocking on kevarim by techiyas hameisim and the eqivilant of 'Ani Yosef' "OY lanu Miyom Hadid Oy lanu Miyom Hatocheicha!!"
And yehuda, despite the ma'aseh with tamar, despite the great shame of facing a Beis din consisting of his tatte Yaakov (who could say REuvain rayshin oni), his zaydeh Yitzchak (pachad Yitzchak)and the ribono shel olam (?..ain beis din shakul..?). And it was before this beis din that he said "tzadka...." and the ribino shel olam finnished it for him ...MIMENI" . And even so he picked himself up, Gur Aryeh Yehuda, and he would suffer no defeat to shame. He wouldn't slow, and souldn't allow himself to weaken his battle.
Read the medrash inside, there is no way to summerise it [the whole vikuach].
Here it is Bekitzur from Ois 3 (typed by word recognition software): א'ר׳ש בן לקיש משל לשגי
אתליטין תפושים זה בזה כיון שהרגיש אהד מהן שהוא בא להנצח אמר עכשיו יגצחגי ואגי
גחבייש בפני הכל מה עשה גשקו על ידיו ושככה חמתו של אתליטיה הגדול . אף יוסף ביון
שתרגיש שעלתה הטתו של יהודה גחירא שלא יחבייש לפגי חטצרים מיד אמר לאחיו אני יוסף אתיכם ולא יכלו לענות אותו
See it in print here
http://hebrewbooks.org/pdfpager.aspx?req=14123&st=&pgnum=103 If you want additional printings here they are
http://hebrewbooks.org/home.aspx and cut/paste this into the "Title" search box מדרש תנחומא