It might have a kiss or two and there are some extras made on Twitter that you can access here that does have sex in it but it isn’t authorized by the people publishing the actual work and it is still a little bit censored as well. I can send a link to the extras because someone did publish them on here.
http://www.mangago.me/read-manga/mo_dao_zu_shi_incense_burner_dj/ It says doujinshi but these scene are in the canon of the novel so have a blast
Is Mo Dao Zu Shi actual shounen ai or is it like heavily censored "oh wow look best buds haha" because its from China