If someone is 'invading my space' to a fairly large degree, I'll use the putting pressure on thieir arm, leg etc-- leaning into them. What I really hate is when someone falls asleep and keeps leaning into me sound asleep-- with that the usual 'pressure' only seems to work to wake them up a bit, they then generally fall right back asleep-- drool, snoring & all! YECH...

PS- when I first read this topic, I thought it was about the 'kissy, huggy types of hellos--- which I also hate, even when I know someone--- I am not a HUGGER, and always feel embarrassed when people I sometimes barely know (and even those I know well) do the kissing, envading personal space thing!