What to do?

[lynars]

played a £100 NL game on crypto when this hand came up. Dont got any specific read on button in this hand couse he just sat down at the table. We both got close to £100 each before this pot occurs.

Folded to the button who limps in.
SB completes an i make it £4 to go with A [img]/images/graemlins/heart.gif[/img] A [img]/images/graemlins/club.gif[/img]
Button calls me and SB folds.

Flop (£9): J [img]/images/graemlins/club.gif[/img] 6 [img]/images/graemlins/club.gif[/img] 3 [img]/images/graemlins/club.gif[/img]

I lead for £8.
Button thinks like 10 seconds then makes it £20.

Whats you move here and why?