If you have some egg mayonnaise left over, make canapés by toasting a slice of bread, and when cold cut into pieces that then top with mayonnaise.
Note: the best bread for this is seed bread, a pure delight.
Remarks
For a more subtle taste, replace parsley with chervil.
If you don't have a forcing bag, use 2 teaspoons instead: 1 for taking mayonnaise from the bowl, and the other one to push it from the first one onto the egg whites.