[Kurikata Juan(後藤寿庵)] Gichigichi Hakase no Ijou na Seiheki (ギチギチ博士の異常な性癖)[2016-03][Gap(Detach)]
From: COMIC Kuriberon (COMIC クリベロン) - Vol.41 [2016-03]
Code:
http://katfile.com/h78ts2k0iwd6.html
Title delivers.
Also tagged as portal or wormhole, but gap is just shorter, there are plenty of stories like this but they mostly vary in creativity.
Immaterial is probabily more rare, particulary those with inner body exploration, only common to ghosts but still very rare.
I am not sure if this is simply body detachment or if he is bending space by using fixed portals, space-bending would be the only difference were this the case.