Two requests

[Yukiko chan]

こんにちは。
1/ I wrote this paragraph some time ago and showed it to nee-chan. She was a bit vague about there being some mistakes and even corrected some of them, but she's too busy to explain in detail. So, I would like to know what mistakes I made here, why they are so, and how I can reformulate them.
一昨日、この文節を書いていました。
「今日は、グレグです。二十一歳で、地球人です。
言語に興味がたくさん あります。日本語を一人で勉強しています, 本とサイトで..
日本文化も大好きで、日本で 年間 勉強していました オランダ人のお友達 が います。彼女から日本のものごと を たくさん聞きました。しかも 日本の神話と 日本史 を読むことが大好きなのです。」
多分、余暇があるなら日本語で手紙をあなたに書いていると思い ます。
2/ Also, someone from another forum showed me this picture. I can understand the words, but I don't know what they exactly refer to, nor why this pic is supposed to be funny.

おねがいします。

 

[Haruspex]

Well, the guy is stomping on the other's d*ck, so err, yeah.

 

[Yukiko chan]

Well, I can see that.. but that would make it a creepy joke at best..

 

[hirashin]

When I was a kid, I and some other kids played a trick of "denki anma" (literally electric massage?) like that picture.

Hope my English is understandable.

Hirashin

 

[Yukiko chan]

When I was a kid, I and some other kids played a trick of "denki anma" (literally electric massage?) like that picture.
Hope my English is understandable.
Hirashin

Sure it is. Can you explain more? I'm very interested to know.
Thanks.

 

[Yukiko chan]

So, no mistake in that paragraph? Or is it so full of mistakes that it was rendered indecipherable?