[Lingo] 大木・おおぱい

[steve smith <sjs@example.com>]

皆、今年も宜しくお願いします。

On the radio just now I heard a couple joking back and forth.  She said 
"大木" and he replied "おおぱい" and they laughed.  It happened several 
times.  I assume that おおぱい means small or few or something like 
that.  Can someone fill me in please?

Thanks
Steve S.