So I wasn't sure before but I'm pretty certain now; it seems that succubi don't actually have to have sex with people in this world, just give them lewd dreams. The dreams then let them siphon off "life energy," which isn't sperm since the succubus says she's getting life energy even with the MC's wholesome dreams.
This setting better explains her shy attitude, which makes a lot more sense for someone who hasn't been banging people left and right. The boss also seems to use her lewdness as a workplace tool, rather than to actually get into people's pants. Seeing how "moral" she is this chapter, I wouldn't be surprised if she also draws the limit at sexual dreams. Basically, everyone's a lot less lewd than they first appear.
They're just trying to do their jobs and earn a living.
Maybe this was common knowledge and I'm just slow on the uptake, but I felt the need to type this out.