てっする
tessuru

Suru Verb

1. to penetrate; to sink in

Intransitive
Suru Verb

2. to devote oneself (to); to do intently and exclusively

Intransitive
大学だいがくたての新人しんじん資料しりょうつくったり、コピーをとったりと裏方うらかた仕事しごとてっするのだろうと、勝手かって想像そうぞうしていたのですが見事みごと裏切られました。
daigakudetateno shinjinwa shiryōo tsukuttari kopiio tottarito urakatashigotoni tessuru nodarōto katteni sōzō shite ita nodesuga migotoni uragiraremashita.
I had imagined that the newbies fresh from university would probably be stuck with all the backstage work - collecting reference material, getting copies and such but I couldn't have been proved more wrong.
Suru Verb

3. to do throughout (e.g. the night)

Intransitive
よるてっするかいなか。
yoruo tessuruka hika
Should I stay up all night or not?