I'm pretty sure that I recently heard Fr. Ripperger mention this in one of his audio sermons.  (As yes, being a grave sin.)  Same with tongue piercings -- and such individuals should not be given HC until the disgusting ring is removed.

I did hear a sermon about this. 

Fr. Crane gave one, just at the time I was considering getting a small one...(back in my younger, crazier days).  It IS a mortal sin.  And the reasoning is: the body is the temple of the Holy Ghost.  Any tattoos would be a desecration of it.  Thus, it's a mortal sin.  I can't remember if he applied that same precept to multiple body piercings or not, and how women getting their ears pierced would pertain to it, but I DO remember that part quite clearly!

Ladislaus, how you can have spent time in an SSPX seminary and not know this is perplexing, because they teach this, as several others here have attested to.

I don't know whether or not tattoos are a mortal sin (I think this would depend on every particular situation, motive, amount, theme, etc.). They are a sure sign of degeneracy, however. Most especially, in women. I've heard you can tell whether a girl is damaged, just by looking at this indication alone. 

Catholics should reject all degeneracy.

I don't know whether or not tattoos are a mortal sin (I think this would depend on every particular situation, motive, amount, theme, etc.). 

I wonder whether it would qualify as a form of "self-mutilation" which is a sin.

I'm pretty sure that I recently heard Fr. Ripperger mention this in one of his audio sermons.  (As yes, being a grave sin.)  Same with tongue piercings -- and such individuals should not be given HC until the disgusting ring is removed.

Well, tongue piercings entail an objective irreverence for Holy Communion ... which is received on the tongue.

Very few sins do not admit of degrees.  Someone who gets a small tattoo of a cross on his upper arm is not in the same class as the person on whom one cannot even find a patch of natural skin.  To categorically state that tattoos are always mortal sin, or mutilations are a mortal sin is unreasonable and extreme.  Church has never condemned earrings on women and, from the physical standpoint it's entirely the same as piercing the tongue.  Now piercing the tongue is disgusting to most of us, but would it be possible to find a culture where people feel the same way about pierced ears?

I agree that the extreme tattoos most likely involve mortal sin, but someone who gets a small tattoo of a cross or a small rose (as some women do), I really don't think that's any more sinful than wearing an earring.  We're now putting getting a small tattoo in the same category (mortal sin) as, say, fornication?

Just for the record, I do not have any tattoos and so don't have any "skin in the game" as it were.

We're now putting getting a small tattoo in the same category (mortal sin) as, say, fornication?

Who said anything about fornication?  Are you aware that there are degrees of gravity among grave sins?