Judah wants his pledge back, so he sends Hirah to look for the harlot. Hirah is the junior partner in their bond of friendship, and is sent to go where Judah is ashamed to go himself and to do Judah’s dirt work for him.
Judah apparently cared about his reputation enough to want to avoid this scandal, but not enough to avoid behaving in this shameful way in the first place. What games we can play with our own consciences! How easy we think it is to pacify conscience with a few trivial acts while whole areas of wickedness go unchecked. We do not understand what it is that God has put within us, a witness that is very hard to corrupt however much we try to silence it.