If you can’t keep erection with regular clamp, you won’t be able to do it with air lamp either because while it’s safer than regular clamp, it’s not as firm.
Big Girtha claims you don’t have to maintain erection while clamping, just expansion. If you can keep expansion past your normal girth even while semi in the clamp, you’re doing it right.
I tried this approach, but couldn’t keep it not hard while clamped. :p