One would think the googirl is secreting some sort of contact poison from its surface, numbing and intoxicating its prey so it remains stationary long enough to be digested.
If you right click on the picture, you should see a small menu. One of the choices is Properties. Click on that and read through the bottom line. It should be lots so just highlight some of them to read the rest.
Interesting, but the properties bottom line just lists the tags, and the tags do not make it clear if they are both slime girls or if the slime girl is digesting a human girl.
googirl, monster girl and slime were all used to tag the blue slime girls. Probably...
Hmm, When I right click a menu pops up and the bottom most option is to view it's properties. On the very bottom of the propeties, it says blue_hair breasts double_penetration googirl melting monster_googirl orgasm silver_hair slime tentacles torn_clothes yuri