if i were to bid , i would double showing willingness to bid 6S but i do not think this is the hand for it . My offense to defense ratio is good but not exceptionnal . Not clear the opponents know what they are doing and even if 5S is actually a 3 suiter with a spade void,it is unclear they have landed into their best contract (for all I know they may be cold for 7C or actually belong to 6D or 6H ).