This is when there is one female and four males that all have over-sized penises are having "gang banging". The girl must be getting sexual pleasures from the anus, vagina, mouth, and breasts. All four men ejaculate simultaneously and she will be "full from your cream". The Texan part of this term comes from the saying "Everything's bigger in Texas" and the "cream filling" comes from your sperm and the other three's sperm "filling her up".
Stacey-"Never try a Texan Cream Filling Kim."
Stacey-"I tried it, it hurts"
Kim-"Sorry, we can't be friends Stacey, I hate whores."