to kiss, (implied to be with a lover)
If he tried to swap spit with your sister and he had something like that, he really must be dense.
by The Return of Light Joker November 24, 2009
to French kiss; to snog
We'd park by the lake and just swap spit for hours. Swapping spit is so much fun.
by mandingoe May 24, 2004
Julie and Johnny went behind the bleachers to "swap-spit."
by Polabear August 11, 2003