From teories that I seen I liked a lot one that Luffy has space manipulation devil fruit.
Meaning till now he could change only his own shape. Appearing to be rubber as his body is simply altering its shape within some limitations.
This way Luffys awakening could be not only making everything around him appear bouncy but for example if he could strech floor or walls at will he could avoid attack/ place someone in line of his attack just by using awakening. His imagination would be only limit to ways of using such power. I guess tree sap or mythical zoan model sun god is more likely but I liked space bending the most. Cannot wait for new chapter..