Tex. Penal Code § 2.05

(a) Except as provided by Subsection (b), when this code or another penal law establishes a presumption with respect to any fact, it has the following consequences:

(1) if there is sufficient evidence of the facts that give rise to the presumption, the issue of the existence of the presumed fact must be submitted to the jury, unless the court is satisfied that the evidence as a whole clearly precludes a finding beyond a reasonable doubt of the presumed fact; and

(2) if the existence of the presumed fact is submitted to the jury, the court shall charge the jury, in terms of the presumption and the specific element to which it applies, as follows:

(A) that the facts giving rise to the presumption must be proven beyond a reasonable doubt;

(B) that if such facts are proven beyond a reasonable doubt the jury may find that the element of the offense sought to be presumed exists, but it is not bound to so find;

(C) that even though the jury may find the existence of such element, the state must prove beyond a reasonable doubt each of the other elements of the offense charged; and

(D) if the jury has a reasonable doubt as to the existence of a fact or facts giving rise to the presumption, the presumption fails and the jury shall not consider the presumption for any purpose.

(b) When this code or another penal law establishes a presumption in favor of the defendant with respect to any fact, it has the following consequences:

(1) if there is sufficient evidence of the facts that give rise to the presumption, the issue of the existence of the presumed fact must be submitted to the jury unless the court is satisfied that the evidence as a whole clearly precludes a finding beyond a reasonable doubt of the presumed fact; and

(2) if the existence of the presumed fact is submitted to the jury, the court shall charge the jury, in terms of the presumption, that:

(A) the presumption applies unless the state proves beyond a reasonable doubt that the facts giving rise to the presumption do not exist;

(B) if the state fails to prove beyond a reasonable doubt that the facts giving rise to the presumption do not exist, the jury must find that the presumed fact exists;

(C) even though the jury may find that the presumed fact does not exist, the state must prove beyond a reasonable doubt each of the elements of the offense charged; and

(D) if the jury has a reasonable doubt as to whether the presumed fact exists, the presumption applies and the jury must consider the presumed fact to exist.