You need to be on Kim's manly path. For that:
In the conversation with Kim at the café in chapter three, you have to pick the option:
- You have nothing to worry about, just leave me out of it (cunning)
And do have a total amount of manly points superior than sensitive points.
Then, at the end of the scene, pick:
- What's in it for me? (cunning)
And then:
- Deal (cunning)
You will then be on Kim's manly path and be able to get the handjob scene in chapter 4 (and more in chapter 5). Check the profile menu to see in which path you are.
I hope that's clear enough.