SoCal* Relative to the rest of the country, they have far more exposure to hotter girls so they're operating from a place of abundance & are generally more unreactive; plus, California is generally pretty sex-positive and less religious than the Bible Belt or the Rust Belt so they have less hangups going in.
Southerners are hit or miss but generally have too many societal hangups to be anything other than efficient serial monogamists. Guys from the midwest are the worst (scarcity, religiousity + small town values). Northeast city guys are usually hella aggressive & easily distractable--get them qualifying & they don't stop. Texans are reactive & easy to get to clown themselves out.
Guys from Australia kill it in the states--California-type vibe & the accent. But really, regardless of where you're from (except less romanticized states like Ohio or Wisconsin or Kansas), you get a boost when traveling in other regions.