What does the cryptic crossword clue "Being amorous in the centre of Birmingham with Elvis? (7)" mean?

The wordplay uses a charade (building blocks). NEC (synonym="NEC") + KING (synonym="KING") = NECKING The answer is NECKING.

Being amorous in the centre of Birmingham with Elvis? (7)

Guardian Cryptic #26511 | 9 Across | 2015-03-05 flower