You have to look all over your town for him from 6PM onwards. I think the event ends around 12AM. You have to talk to him 5 times in order to get just one present (one reason why I dislike the GCN version's Toy Day, besides the music). You can then change clothes while he is not looking and then you have to find him another 5 times in order to get another present. Soon he will realise but he will just laugh though he won't give you anything.