You simply add another @font-face
rule:
@font-face {
font-family: CustomFont;
src: url('CustomFont.ttf');
}
@font-face {
font-family: CustomFont2;
src: url('CustomFont2.ttf');
}
If your second font still doesn't work, make sure you're spelling its typeface name and its file name correctly, your browser caches are behaving, your OS isn't messing around with a font of the same name, etc.