By the way, over the years of keeping snakes, some of us (myself included) have found that the "best way" to encourage a snake to "go" is just to put on our best fancy shirts (dry clean is a bonus) and let our snakes cuddle around our shoulders for a while...Nothing like a surprise, eh?
(Actually, it's just that handling- the snake moving around more- that tends to get "results", ahem... When they're "couch-potatoes" they just don't feel the need to defecate so soon.) But please don't try to "manipulate" them into defecating.