What does the cryptic crossword clue "Bottom smacks warming couple at night? (3,5)" mean?

The wordplay uses a charade (building blocks). BED (synonym="bottom") + SOCKS (synonym="hits, smacks") = BEDSOCKS The answer is BEDSOCKS.

Bottom smacks warming couple at night? (3,5)

Guardian Cryptic #29336 | 16 Down | 2024-03-21 flower