A woman is holding the cheeks of a man on the beach.
A woman is grabbing the butt cheeks of a man on the beach while another man watches.
Not all cheeks are butt cheeks, and being on the beach does not imply another man watching.
exists e1 x1 x2 x3 x4.(n_beach(x4) & n_cheek(x2) & Theme(e1,x2) & Actor(e1,x1) & v_hold(e1) & of(x2,x3) & on(x3,x4) & n_man(x3) & n_woman(x1))
exists e1 p1 x1 x2 x3 x4 x5.(n_beach(x5) & n_cheek(x2) & of(x2,x3) & n_butt(x3) & exists e2 x6.(Actor(e2,x6) & v_watch(e2) & n_man(x6) & -(x6 = x4)) & n_man(x4) & n_man(x4) & while(e1,p1) & Theme(e1,x2) & Actor(e1,x1) & v_grab(e1) & of(x2,x4) & on(x4,x5) & n_woman(x1))