it sounds like /ɜ:/ in english

Just open your mouth a little bit, and then your tongue not to bend.

Sounds like ERR

For me in my English accent, lol, it sounds just like when you say 'errrr'. You know when something is disgusting or you are stuck for what to say.

Borrowing from Erinchan's IPA: you can hear the "/ɜ:/" sound here. Most of my teachers pronounce it a little farther back in the throat /ɞ:/ only a slight difference. The IPA can be very useful, especially if you're not able to communicate regularly with a native speaker. In English, the closest approximations would be "eh-sheen" or "uh-sheen" for 恶心 (with appropriate tones, of course) and "eh-luo-sih" or "uh-luo-sih" for 俄罗斯 http://www.internationalphoneticalphabet.org/ipa-sounds/ipa-chart-with-sounds/