What do you guys use to seal around freeze plugs?

[priderocks]

Do you need to seal around freeze plugs with anything special?

[72cudamaan]

Permatex aviation sealer works great.

[femtnmax]

 
I also use Permatex High Tack Gasket sealant, has the brush built into the cap, the goo is dark red in color.  I brush the permatex onto block, then install the freeze plug.
An important installation tip, assuming you don't have the factory service tool, then fit a socket to contact the OD of the freeze plug, NOT fit inside.  If fit the socket to inside, when installing the plug can slightly shrink the diameter and ON OCCASION will cause a leak.   Some people may disagree with me, but I have seen them leak.  THe factory service tools apply pressure against the OD of the plug. 
When your turning wrenches for a living, and paid commission only...a leak just cost you the profit of the entire job. 

[ntstlgl1970]

 
Also have used the brown thick permatex (2A?) stuff with success. All the freeze plug tools I have drive on the outside edge of the plug - keeps you from installing them too deep as well. This is more critical if you choose to install brass plugs since they deform more easily

[Skunkworks Challenger]

Permatex sealer works well but when driving plugs the method varies with the type of plug being used.  A cup style is driven around the edges but the domed disk type will not seal if driven around the edges.  They must be at least "seated" from the middle to fully expand them to the opening. PK

[vinb]

If your doing them on the engine stand and don't have the proper tool or socket , a piece of hard wood will work too...

[mopar12372]

permatex 2b . you can buy it at autozone , oreillys, napa . use it on tranny seals around the out side / crank seals ect.