I need to know how marshmallow fondant tastes?!

Fondant doesn't really have a taste, it is just sweet. The texture is chewy. It is similar to eating a vanilla Tootsie Roll.
Marshmallow fondant is the easiest to make. It is not quite as smooth in texture and as stretchy to work with as the regular fondant.
The regular fondant can be kept in an air tight container for like a year and is still usable. I find the marshmallow fondant gets crumbly if you try to keep it for later use.

MARSHMALLOW FONDANT
16 oz. mini marshmallows
2-5 T. water
2 pounds powdered sugar
1/2 cup Crisco
Melt marshmallows and 2 T. water in microwave. Put bowl in microwave for 30 sec. Stir. Put back in for 30 sec. Stir. Repeat until all melted. (2 1/2 min. total) Put 3/4 of powdered sugar in.
Grease yor hands generously....grease countertop....dump contents of bowl. Knead like bread dough. Add rest of powdered sugar and knead in. If it is too dry, add more water. Kneading takes about 8 minutes. When smooth double wrap in plastic wrap. Let sit overnight.

ROLLED FONDANT
2 T. freshly squeezed lemon juice
1 T water
1 T unflavored powdered gelatin...1 pkt.
2 T solid white vegetable shortening
1/2 cup light corn syrup
1 T glycerine
8 cups (about 2 lbs.) confectioners sugar
non-stick vegetable cooking spray, for working with fondant.

In a 2 cup glass measuring cup, combine the lemon juice and water. Sprinkle the gelatin over the top of the mixture and let the gelatin soften for 3 minutes. Place the glass measuring cup in a small saucepan of simmering water and stir the mixture for 2 to 3 minutes, until the gelatin is completely dissolved. Stir in the shortening until melted. Blend in the corn syrup and glycerine. Remove the glass measuring cup from the pan of water.
Place the sugar in a large mixing bowl and make a well in the center. Pour the gelatin mixture into the well and stir with a wooden spoon until blended the mix with your hands and vigorously knead the mixture until smooth. If the mixture seems very dry, add several drops of water and knead well. If the mixture seems too sticky knead in more confectioners sugar. The fondant should be malleeable like modeling clay.
Rub one side of a disposable cloth towel (such as handiwipe) with enough shortening to coat it well and wrap the fondant in it. Then overwrap in plastic and place in airtight container. Let the fondant "ripen" overnight before using.
Knead the fondant until fondant is malleable enough to roll. Spray a smooth, clean work surface such as marble or formica top with non stick vegetable cooking spray. Also coat a large, heavy rolling pin with the spray. Form the piece of fondant into a flat disk and roll it into 16" diameter with 1/4 inch thickness. Lift up and rotate the circle every two or three rolls to ensure that it it not sticking. If necessary, respray the work surface. Work quickly to prevent the fondant from drying out.
Remove the iced cake from the refrigerator. Slip your fists palm side down under the fondant being careful not to stretch or tear it. Lift the fondant onto the cake covering it as evenly as possible. Using the palm of your hand, smooth the top and then sides of the cake as evenly covered and fondant is smooth. The oil from your hands will give it a lustrous glow. With a pizza cutter or scissors, trim the bottom edge of the cake to remove the excess fondant.
Now you are ready to decorate your cake....ENJOY!