Doujinshi: Getsuyoubi no Tawawa 月曜日のたわわ (C89, circle: Himaru Nyuugyou 比村乳業)
Translation
Context: a salaryman recalls the backstory.
hyonna koto kara ochikadzuki ni nari ひょんなことからお近づきになり Due to something strange [happening], [we] became acquaintances, [then]...
nari is a ren'youkei 連用形 and can be used to connect an event to a subsequent one, translating here as "to become X, and then..."
{iinkai daka de rasshu-ji ni toukou shinakya naranai} getsuyoubi dake 委員会だかでラッシュ時に登校しなきゃならない月曜日だけ Only in the Mondays, [when] {[she] has to go to school at rush hours due to [something related] to a [school] committee}...
{chikan boushi no bodhii gaado wo oosetsukaru} you ni nattari shite 痴漢防止のボディーガードを仰せつかるようになったりして [I] end up becoming {[her] anti-groper body guard}.
boushi 防止 means "prevention," so something chikan-boushi is something that prevents chikan, i.e. prevents gropers, anti-gropers.
