You'd do anything to stay out of jail. But if that's the kind of pay the guard wanted, the perpetrator has to do his best. And so this guy fucked her well, fucked her in all positions, so that the guard herself has wanted to taste his cock. And the ending on her belly completed the payoff. All debts had been paid. Here comes the long-awaited freedom.
Not fully understood what the stepmother was talking to him in the beginning, but judging by the further development of events, obviously complaining about his hard feminine lot - large breasts, in her case, which is difficult to wear without constant massage. And the massage of her breasts, as well as of her whole body. And that's what his dark-skinned girlfriend was talking about, before she went to bed with them, I understood at once - she sympathized with her stepmother and offered her help! That's how it was, wasn't it?