Fattening others

Always been into the idea of making my feedee a gainer shake, is there anything that i could add to make it better for gaining or making it yummy? Only ever really used mass gainer, pb, a bit of icecream and milk
And ps question,

double cream

I’ve recently got into gainer shakes and they are incredible !!! I go with chocolate milk, double cream, ice cream, condensed milk, golden syrup and cake mix. All topped off with whipped cream and sprinkles. They have made my tummy and tits sooooo soft and saggy I absolutely love it !! Hope that helps 😘