For a mature lady, the very fact that she is given in her mouth and cum in the same place is like a balm to her body. She feels that she hasn't lost her attractiveness and competes with her younger girlfriends on an equal footing. And the attention of the males tickles her vagina so much.
And did you see how the brunette's eyes lit up when she saw the money? Where did her modesty go... and gave it to her in the ass!