I'm feeling kinky does Mangago have a tag for ass spreading yaoi lmao. I need to see some ...

http://www.mangago.zone/read-manga/ao_no_exorcist_dj_distract/
(Page 18)

http://www.mangago.zone/read-manga/mob_for_jack/
(Pretty much every other page tbh)

http://www.mangago.zone/read-manga/sweet_heart_trigger/
(Chapter 2 Page 15)

http://www.mangago.zone/read-manga/takane_no_hana_wa_chirasaretai/
(Chapter 1 Page 33)

http://www.mangago.zone/home/mangatopic/1675193/
There's a lot of suggestions here too, seems somewhat similar to what you're looking for. Enjoy!

the question isn't if mangago has a tag, it's has a user made that tag (≧∀≦) so probably there is xD
try some variation of word on what you want in the tag bar

http://www.mangago.zone/read-manga/renai_rubi_no_tadashii_furikata/

Why am I getting likes instead of answers (╯°Д °)╯╧╧

Thank you for those who answered but most of them are "leg spreading" instead of ass spreading. Ass spreading is when they seme puts his finger into the uke's hole and spreads it wide. Like http://www.mangago.zone/read-manga/messiah_no_yakubi/mi/mi_chapter-1/ page 16.

the one i posted should have close up of that, if i remember it correctly xD