"Seven days of impurity."
Actually it's more like 12-ish. The Torah states that if a woman experiences an unusual flow, she needs to wait for it to end, and then count seven clean days. For the last ~1600 years, we operate with the rule of thumb that we don't know what's called "usual" or "unusual", and thus it's duration of bleeding, or 5 days, whichever is more; followed by 7 clean days. AND then an IMMERSION IN A MIKVAH (ritual bath). Without the immersion she's still impure.
But to answer your question. The Talmud quotes a Rabbi Yochanan ben Dahavai -- "as holy as G-d's ministering angels" -- that if you look there, you'll die; if you kiss that, your children will be crippled, all sorts of awful stuff. The Talmud acknowledges this ascetic opinion, and then simply states: "but the majority of rabbis opine otherwise, and the law does not follow Rabbi Yochanan ben Dahavai."
At first glance, thus, everything would be permitted. Some later rabbis, however, read the conclusion as "everything -- means everything except for one or two things." Meanwhile, an ascetic tradition -- whose influences may have been Kabbalistic and/or Christian -- certainly influenced several major later codifiers of Jewish law. The Karo/Issreles code from the 1500s doesn't seem too thrilled with intimacy as anything other than a necessity, and proscribes several acts accordingly. (Though fascinatingly, their code addresses the subject twice -- once in the section relating to an individual and his personal ritual obligations, using very stern language; the other in the section on laws of marriage, and suddenly as there are now two people in the room, the language isn't nearly as harsh.)
Similarly, the Talmud speaks of a prohibition called "don't do gross things", for instance, while certain kinds of locusts are kosher (at least in theory) and they don't require ritual slaughter, you shouldn't swallow a live one as it's wiggling -- "don't do gross things." Certain rabbis applied this language to certain intimate acts, which raises the question of subjectivity and whose definition of "gross" if it wasn't already described by the Talmud.
Today, there are contemporary rabbis with opinions running the gamut from a very ascetic view to a very permissive one -- with similar discussion whether the more ascetic language of some texts was intended as law, custom, suggestion, or an appropriate act of piety for those on the right spiritual level.
Contemporary authority Rabbi Yehuda Herzl Henkin sets out his opinion in Bnei Banim 4:16 (and the next few essays), for those who read rabbinic Hebrew. He has declined to publish his stance in English, however if you email someone at www.yoatzot.org, they will privately describe his ruling.