the realdefinition of "splonking" is observing caves. Well think of that in the same sense but with a dirty mind. A guy observing or more a girls 'cave' is splonking.
So were you a splonker last night?
Yeah but as i was splonking, her mom walked in, which ended up causing her to sploosh in my face. it was delicious.
Splanding techniques vary but usually requires assistance from a drug like MDMA combined with a psychedelic - you must be loose but also attuned, leaning without recognising gravities influence.