I have had a lot of anonymous sex where I didn´t even know the other guys nationality.
But I KNOW for sure that I have been with the following 34 nationalities:
Denmark (obviously...having been with about 100 Danes I can tell that the average size for Danes is about 6 inches...but I have had a few very big around 8 inches)
Greenland (they tend to be fairly big...and thick....many from 6-8 inches)
Sweden (I have had a few nice blond young swedes, because I live only 25 km. away from Swedens third biggest town, Malmö....swedes generally are not small, I would say they are pretty big....)
Iceland (a nice 20 yo blond guy with a big 7 inches dick...and a hot hot ass)
Norway (a mature man who gave me a blowjob in a park)
Germany (I have been to Berlin and Hamburg af few times, so I have been with maybe 15 Germans....their size is more or less like that of the Danes, I believe, average probably 6 inches)
England (the biggest guy I have had: 10 inches)
Russia (last year I met a crazy but nice 18 yo Russian in the park..he was 7 inches long, very sexy blond guy)
France (he was only 4 inches, 26 old and chubby..)
Spain (I actually had a boyfriend from spain...5 inches only)
Portugal (I once fucked a portuguese trans)
Italy (a 26 old nice guy from Turin...normal dick sixe...6 inches)
Romania (a very sexy 21 yo old guy, nice ass...normal dick)
Greece (still know him...20 yo and very hung...8½ inches!)
Turkey (I have been with at least 5-6 turkes...all normal size)
Brazil (I have been with 3-4 Brazilians....average sized)
Chile (two young guys, 19 and 20 yo...one was 6 inches, the other one 7 inches..but very sweet and nice..)
Mexico (24 yo, 7 inches..nice body...and lovely guy)
Colombia (a very young guy, he was 16 - yes, legal age in my country! -, normal 6 inches long cock)
USA (a 19 yo horny guy with a long skinny dick...9 inches long!)
Iran (two young guys, one was 5 inches, the other 6 - not big)
Philippines Island (two guys, a 24 yo guy with 6 inches and a 19 yo transsexual with a small 5 inches penis)
Palestina (all cut, but normally sized)
Israel (one was a late teen guy, small 5 inches dick, the other 27-28 yo and 7 inches)
Kazakhstan (19 yo guy with a small 4½ incher)
Somalia (a 19 yo tall skinny boy with a long 8 inches long dick)
Japan (I have been with at least 4-5 japaneses, they tend to be small, even that one of them, a guy around 20-22 yo, was tall, skinny and had a nice pretty big 6½-7 inches cock)
China (chinese men tend to have short, but thick penises...but not THAT small, mostly 5-6 inches)
South Korea (he was pretty small, 5 inches, a chubby guy)
Maleysia (they also tend to be around 4½-6 inches)
Singapore (a nice 28 yo guy, but with a small 5 incher)
Indonesia (Indonesian guys tend to be quite small and boyish looking, also with small penises around 5 inches)
India (a tall guy with a normal dick)
Pakistan (I know one pakistan guy with a big 7½ inches dick, 30 yo old, but the other Pakistan guys I have had were 5-6½ inches, pretty normal).
.....and certainly there have been more nationalities