This worked for me for water icing or chocolate:
Write your words in pencil on a sheet of greaseproof paper then tape it to a chopping board. Give it a dusting of icing sugar.
Pipe out the words with your "icing" and leave it to settle for a few mins.
Place the board with the greaseproof and icing in the freezer and let it set/freeze.
You can sometimes lift the frozen icing directly off the greaseproof using a metal spatula or thin knife and carefully lift the writing onto the cake.
If not, untape the greaseproof from the board and slide it till the writing reaches the edge then with a downward motion of the paper peel the icing off onto your worktop.
Tip: it is never to early for vodka, esp the flavoured ones.
