It has to be the "tears" like crying, not like ripping, and here's why.
You know why lawyers never get hemorrhoids? Because they're perfect assholes.
(And I did cry at least three tears in law school, but I never admit it in public while using my real name.)
While many of us at the Bar (the legal bar, not the titty bar) remember the astonishing result of the vote the estimable ShysterJon referenced, I have had a conversation with one guy who said his former client filed a grievance against him that included a complaint that he "used" her for sex during the course of the representation. The grievance committee didn't necessarily cite him for breaking the non-existing "no nooky" rule, but to my friend it was a huge factor in them being extra zealous in finding other violations of various provisions of the DRPC (colloquially, the "ethics rules"), and in assessing a severe penalty that he was pretty sure would have been no more than a private reprimand under less sexy circumstances.
And no, I WILL NOT provide this lawyer's name to you if you pm me, so save the key strokes. And I don't care who you are.
So my thought -- yes, it's true that in Texas at least, it's not a direct violation of the DRPC to have sex with a client. If you do it as a "trade for services" however, it is a violation of Rule 1.04 ("A lawyer shall not enter into an arrangement for, charte, or collect an illegal fee or unconscionable fee.") It also will probably be alleged to be a violation of Rule 8.04(a)(2) ("A lawyer shall not ... commit a ... criminal act [prostitution or solicitation of prostitution] that reflects adversely on the lawyer's honesty, trustworthiness or fitness as a lawyer in other respects ..."). So, if you hire a lawyer who is willing to trade for sexual services as the original poster asks, you're not hiring a very good, a very smart, or very careful lawyer, and you should keep shopping.