I’ve been wondering about this from time to time for a few years now: What is the origin of the phrase “making out”? Does anybody know?
Just a WAG, but I assume that it simply came from the old term ‘make out’ meaning to manage to do something. As in ‘How did you make out at the job interview?’. In that context asking ‘How did you make out?’ is the same as asking ‘How far did you get?’. The kind of comment teenage boys are particualrly noted for asking (eg 'How’d you make out? Get to second base?)
Since any sort of sexual activity seems to automatically generate eupemisms it isn’t hard to see how it came to apply specifically to what is essentially foreplay.
BTW welcome to SDMB.
According to Cassell’s Dictionary of Slang:
make out v. 1 [mid-19C+] (orig. US) to get along, to make the grade, to succeed. 2 [1930’s+] (US) to seduce a woman. 3 [1940’s+] (US) to indulge in hetero- or homosexual foreplay or petting but not necessarily intercourse.
make out with yourself v. [1950’s+] (US) to masturbate.
This answers a question I have often wondered about, namely which came first, dual-person sex or self-gratification. 