In the rich text editor:
@lavenderrain
In a comment:
[lavenderrain](https://painted-relics.com/user/lavenderrain)
For Names and Avatars:
In the rich text editor:
%lavenderrain
In a comment:
[](https://painted-relics.com/user/lavenderrain) [lavenderrain](https://painted-relics.com/user/lavenderrain)