Excellent question! Originally the scope of P&P was for specific effects to add or utilize them, with each representing more than just momentary pain or damage but rather the intrinsic kink-based sensation related to them. However, based on feedback, we added rules in book 2 to make generic actions for each. In short it's "a creature can as an action add either 1 Pain or Pleasure to themselves or another willing creature within 5 feet of them." Anything beyond there is reliant on what items or kink implements are being utilized.
Viewing post in Help, how to Pleasure and Pain?
Ah okay, that does clarify some parts of my question and wondering. Then i'll have to see how the new Set of Rules elaborate on it. :3
Because there is for example the Path of the Titan Barbarian that seem to not have any class specific Abilities or Effects to utilize Pleasure or Pain for themself or apply said Pleasure/Pain to their opponment and for that there isn't much written, cirling back to my original question, on how a player character would be able to apply Pleasure or Pain to an Opponment on a regular basis, like with their bare hands in a brawl or use of regular common weapon.
If not for themself, than at least to the benefit for their Party to utilize the gained Points on their Opponment.
For now it seems it's mostly just up for the GM to determine what and when Pleasure and Pain is dealt or gained at such unspecified Situation.