I'm looking for the name of the yaoi manga where Guy A can't get an erection after a traumatizing encounter with a women (or something like that) so his friend give him this bottle of love juice (aphrodisiac). He leaves it in his room when Guy B comes over (I think that they had just recently met) Guy A leaves the room and Guy B ends up drinking the love juice. Guy A ends up having to help Guy B and in the process ends up getting his first erection in a long time. Guy A ends up nervous so instead of having sex he shoves the bottle in Guy B's hole.
There's more to the story but this is what I remember. I would really apreciate it if anyone remembered what thus manga is called.

It should be S..Friend =3

Thank you so much! I have spent a week looking for this. Thank you so much.