Someone riding sideways on a motorcycle.
The person wanted to show off to the crowd of onlookers.
riding  doesn't always mean show off
exists e1 x1 x2.(on(e1,x2) & n_motorcycle(x2) & Actor(e1,x1) & v_sideway(e1) & n_riding(x1))
exists e1 p1 x1 x2.(n_crowd(x2) & n_person(x1) & Topic(e1,p1) & Actor(e1,x1) & v_want(e1) & exists e2 s1 x3.(a_off(s1) & Manner(e2,s1) & to(e2,x2) & of(x2,x3) & n_onlooker(x3) & Actor(e2,x1) & v_show(e2)))