Köhler's Indogermanisches Wörterbuch (letter E):
*eibh-, *oibh-, *i̯̪ebh-, idg., V.: nhd. beischlafen; ne. copulate; RB.: Pokorny 298 (439/20), ind., gr., ill., germ., slaw.;
Pokorny's Indogermanisches Etymologisches Woerterbuch (p. 298):
Root: eibh- (: oibh-), i̯ebh-
English meaning: to copulate
...
Material: Ai. ya/bhati 'futuit'; ... ; slav. *i̯ebo: 'futuo:' in russ. jebu/, jeti/, skr. je\be^m, je\bati (mit neugebildetem Infinitiv), usw.
To illustrate, let me quote from Calvert Watkins' phenomenal How to Kill a Dragon. In chapter 25, professor Watkins describes a fascinating Indo-European ritual (involving horses, young women and some erotic imagery) known in the Vedas as Aśvamedha. The ritual was accompanied by a "litany of mantras" one of which is given below:
ámbe, ámbike, ámbālike
ná me yabhati káś caná;
sásasty aśvakáḥ
Compare the English translation provided by Watkins:ná me yabhati káś caná;
sásasty aśvakáḥ
Mother, dear mother, little mother,
noone is fucking me;
the bad little horse is asleep.
noone is fucking me;
the bad little horse is asleep.
And a Slovak translation by me (courtesy of Monier-Williams Sanskrit dictionary) which is a bit more faithful to the original. Not that professor Watkins is a bad translator, far from it. It's just that the English language has lost many PIE structures most Slavic languages have preserved. Like the the case system (Nominative: amba, Vocative: ambe!) and the diminutive form (amba - ambika - ambālika). NB the first line:
Mamo, mamko, mamičko,
nikto ma nepojebe;
zlý koník už zaspal.
nikto ma nepojebe;
zlý koník už zaspal.
According to professor Watkins, the verb yabhati was considered as vulgar in Vedic Sanskrit as its counterparts are in modern English or Russian (HTKAD p. 274, footnote 12). I wish he'd included more evidence (and if anyone has any, please come forward), but nevertheless, I think we can take his word for it. So there.
It is interesting that of all the offshoots of the PIE tree, this particular root with all its connotations has only survived (in pristine condition, nonetheless) in Slavic languages where - as I'm sure anyone will tell you - it still enjoys immense popularity. So remember, my Slavic friends: when life gets you down and you feel the need, do not hesitate to use any and all words derived from this root. By doing so, you are certainly not contributing to the corrosion of our society as some would have you believe. On the contrary: you are engaging in a healthy activity which relieves your frustration and cleanses your mind of aggression. And all of that in a way which lets us express and celebrate our Indo-European heritage. After all, it's only Sanskrit and us!