"a kiss," 1560s; probably of imitative origin, as are Welsh and Gaelic bus "kiss, lip," French baiser "kiss" (12c., from Latin basiare), Spanish buz, German dialectal Buss.
To talk about; gossip over: Quit bussin' about my shoes
[1980s+ Teenagers; perhaps a survival of British dialect buss, ''mutter, murmur busily, buzz,'' attested from the 1500s]