Basically a manga that center on the topic's related theme where physical intimacy - isn't sough after with pleasure or personal interests in mind but instead it's maintained due to a condition, uncommon/cynical professions, or a universal-purpose - between heterosexual parties. The tone of the physical intimacy can range from light (kisses/hugs), mild (foreplay), or to heavy (sexual intercourse). Any demographic would do as long as the series is scanlated.

Further detailing of the three categories (not the intimacy level 😛 ..... 🤣 )

Conditions (illness)
Sakuranbo Syndrome - Saliva is required for the cure.

Work (uncommon/cynical profession)
Her Majesty Dog - Kisses as energy source. Uncommon Profession: Ghost Hunter/Detective.
Tokyo Red Hood (closest match I know of - this one is not bad if you keep an open mind 😁 ) - Assassination through sexual intercourse. Cynical Profession: Assassins/Syndicate
-I know of other sources relating to this catagory like a movie called Naked Weapon that deals with assassination through heavy physical intimacy and an ova/eroge game titled Bible Black that involves uncommon profession where they collect male sperms for Witchcraft experiments (not a very good example I know...but that's all I can remember 🙁 ).

Universal Purpose (saving the world/mankind)
Oretama - Foreplay to achieve ejaculation (The Goal).
-Don't mistaken Sundome with this since it's done with personal interests in mind hence a bad example.

Odd request? I know... Just needed something unusual/bizarre to read since I haven't run into much series with these type of similarity, something I found an interest in 🤣 Need to balance my mind from reading quite a few of these romantic stuff lately, before I turn into a 14 year old school girl...no offense 😉

As usual my lists are at your disposal, much thanks!

Edit: omg 😲 ...messed up the title. If a mod would be so kind as to fix it for me, that would be great! Original Intended Title:

Condition is treated/Work (uncommon/cynical profession) or Universal-Purpose is accomplished through physical intimacy between heterosexual parties.

You might like Double Arts. They have to be touching each other's skin at all times.

The sad thing is that the manga was discontinued and the ending was rushed, but it still fits what you're looking for.

If you've ever thought or said "Nice Guys finish last" and really meant it, then you should probably read this LJ post by DivaLion. It's incredibly insightful whether you're male or female.

From a bumper sticker I like:
"If you're gonna ride my ass, at least pull my hair."

Nope the request is not strange. It just your description is twisted and long 😀
is 'the world god only kows' fit what ur looking for?
How about 'my mysterious girlfriend x'?
Or 'sekirei'?
sorry but i don't actually read ur list.

I'm reminded of Dokuhime.

Work: Assassinations by poison [Through touch, kisses, and intercourse].