Responses
The plot you describe kinda sounds like this manga:
Calling by Ootsuki Miu, but the salary man is not on the older side, though.
https://www.mangago.zone/read-manga/calling_ootsuki_miu/
I think it starts with salary man going through the park with a bag with tofu ao nights and hears sounds and I think he tries to safe a girl but it ends up being porn film being shot. The actor takes a liking to him and gives him lots of his videos but I can't remember how they meet again. Don't remember any more.... I really really wanna read it again. Does anybody knows?