wedding bells, n. — Green’s Dictionary of Slang

wedding bells n.

[ety. unknown; ? it ‘rings’ in one’s skull]

(drugs) LSD.

1971		Chronicle-Telegram (Elyria, OH) 16 Mar. 2/7–8: The chart [...] describes LSD as ‘pearly gates,’ ‘heavenly blue’ and ‘wedding bells.’.
2001		ONDCP Street Terms 22: Wedding bells — LSD.