Dragon,
What I'm thinking is that once you remove him from the rock, he is very slipery. And even glue under his foot won't stick. So what might work is what he is suggesting.
You place him in a cup of aquarium water and then flip the cup upside down and let him fall to the bottom of your sand bed. He is sure to pick up the sand pebbles from that. Once he has this, he will be more bouyant, he will be anchored, won't float away.
But if you want him in a special place, you use this glue and since he has those pebbles it will stick better.
This is how I see it from Incysor's instruction: however lets wait for him to replay again,,,,
Mike