Make a fist with your thumb in your palm >> your thumb in your closed fist :
Your thumb knuckle will stick out.
Now put your lips around that knuckle , and without extending your tongue out of your mouth (you don't need to , because
your mouth is around the 'mound' of the knuckle) , start flicking your tongue back and forth sideways. Gently , not madly.
No need to move your head , nor bop up n down , no cause for spastic movements of over-enthusiasm.
Practice this at home , while sitting doing nothing , better yet , while you on EI
x
Once you have built up the tongue muscles to be able to last a while , you transfer this skill to the female mound :
guaranteed results .
There are other ways too of course , but this easiest
.