During sparring in Muay Thai, as two people go in for the clinch and are throwing knees etc., and one opponent tries to regulate the distance by keeping a glove on the other's chest; is it allowed in the rules to use your glove on top of it to hold it down on your chest?
erm I think you can't grab the other guys glove in the rules;
but regardless think of this;
you're in punching distance. You just used your two hands to detain one of his. He's got a free hand and you don't. You're going to eat a knuckle (or elbow since this is thai)-sandwich.
Better things to do; you could slap his hand away and close the distance, or squash his hand between your two bodies with your body. (e.g. go chest to chest with his glove in between, stuck from the pressure).