@nprofile1q... They both look amazing, Oli coping with his overwhelming new sensations, and Mark savoring every second of his brother's reactions. I like how his adult hand holds the boy firmly, while the other softly plays with one the testicles. Oli's clearly enjoying all this sex-play as shown by his face and leaking erection.
Also thanks for the tan lines, dick sizes, and decision on uncut/cut ;)
Are we to assume Mark either doesn't sunbathe or that he does it naked?