Sindarin for "Joyful Gift"?

Concept under discussion is a very generous gift given in response to joyful news, possibly to someone who has nothing to do with it. (A modern example would be, you're at a restaurant and get a call from your realtor that your house just sold for $150,000 over asking price. You give your server a really big tip.)

How about: ann glassui

Ann ‘lassui would just mean “joyful gift.” Perhaps for clarification of the situation in which the gift is given, maybe ann dangweth a siniath ‘lessui (S. gift [of] reply to/for joyful news) could work.

I just noticed this; glassui, as all adjectives in -ui, do not change in their plural form.