In a Slovene Grammar present at this site: www.seelrc.org:8080/grammar/mainframe.jsp?nLanguageID=8, it is written at page 39 that in Slovene exists the form "midva + s/z + instrumental + verb in dual form" in the meaning of "I and another person do something together". Midva z Miranom sva šla v Lendavo. To be fair I've never heard this form (maybe I haven't noticed it). However I'm almost sure it is never used in my zone. I'll rather say "Jaz in Miran sva ...". It is amazing that I was surprised at the Russian form "Мы с братом", not knowing that Slovene has something similiar.